Allow templating requests and response sections

[ryandub]

This needs some serious refactoring, but this is a first pass. Allows for the following in your swagger file:

      x-yoke-integration:
        operation: hello
        request-template: default
        response-template: default

Which will produce something like this after rendering:

      x-amazon-apigateway-integration:
        responses:
          ^402:.*:
            responseTemplates:
              application/json: '{"error": {"code": 402, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '402'
          ^500:.*:
            responseTemplates:
              application/json: '{"error": {"code": 500, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '500'
          ^400:.*:
            responseTemplates:
              application/json: '{"error": {"code": 400, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '400'
          ^412:.*:
            responseTemplates:
              application/json: '{"error": {"code": 412, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '412'
          ^503:.*:
            responseTemplates:
              application/json: '{"error": {"code": 503, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '503'
          ^409:.*:
            responseTemplates:
              application/json: '{"error": {"code": 409, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '409'
          ^407:.*:
            responseTemplates:
              application/json: '{"error": {"code": 407, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '407'
          ^404:.*:
            responseTemplates:
              application/json: '{"error": {"code": 404, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '404'
          ^405:.*:
            responseTemplates:
              application/json: '{"error": {"code": 405, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '405'
          ^410:.*:
            responseTemplates:
              application/json: '{"error": {"code": 410, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '410'
          ^413:.*:
            responseTemplates:
              application/json: '{"error": {"code": 413, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '413'
          ^501:.*:
            responseTemplates:
              application/json: '{"error": {"code": 501, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '501'
          ^300:.*:
            responseTemplates:
              application/json: '{"error": {"code": 300, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '300'
          ^401:.*:
            responseTemplates:
              application/json: '{"error": {"code": 401, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '401'
          ^414:.*:
            responseTemplates:
              application/json: '{"error": {"code": 414, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '414'
          ^307:.*:
            responseTemplates:
              application/json: '{"error": {"code": 307, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '307'
          ^416:.*:
            responseTemplates:
              application/json: '{"error": {"code": 416, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '416'
          ^406:.*:
            responseTemplates:
              application/json: '{"error": {"code": 406, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '406'
          ^504:.*:
            responseTemplates:
              application/json: '{"error": {"code": 504, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '504'
          ^415:.*:
            responseTemplates:
              application/json: '{"error": {"code": 415, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '415'
          ^418:.*:
            responseTemplates:
              application/json: '{"error": {"code": 418, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '418'
          ^304:.*:
            responseTemplates:
              application/json: '{"error": {"code": 304, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '304'
          ^403:.*:
            responseTemplates:
              application/json: '{"error": {"code": 403, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '403'
          ^302:.*:
            responseTemplates:
              application/json: '{"error": {"code": 302, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '302'
          ^305:.*:
            responseTemplates:
              application/json: '{"error": {"code": 305, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '305'
          ^505:.*:
            responseTemplates:
              application/json: '{"error": {"code": 505, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '505'
          default:
            responseTemplates:
              application/json: __passthrough__
            statusCode: '200'
          ^411:.*:
            responseTemplates:
              application/json: '{"error": {"code": 411, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '411'
          ^417:.*:
            responseTemplates:
              application/json: '{"error": {"code": 417, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '417'
          ^303:.*:
            responseTemplates:
              application/json: '{"error": {"code": 303, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '303'
          ^422:.*:
            responseTemplates:
              application/json: '{"error": {"code": 422, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '422'
          ^301:.*:
            responseTemplates:
              application/json: '{"error": {"code": 301, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '301'
          ^502:.*:
            responseTemplates:
              application/json: '{"error": {"code": 502, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '502'
          ^408:.*:
            responseTemplates:
              application/json: '{"error": {"code": 408, "message": $input.json(''$.errorMessage'')}}'
            statusCode: '408'
        uri: arn:aws:apigateway:us-east-1:lambda:path/2015-03-31/functions/arn:aws:lambda:us-east-1:<snip>:function:yokeHelloWorld:foo/invocations
        httpMethod: POST
        requestTemplates:
          application/json: "{\n  \"operation\": \"hello\",\n  \"parameters\": {\n\
            \    \"gateway\": {\n      \"id\": \"$context.apiId\",\n      \"stage\"\
            : \"$context.stage\",\n      \"request-id\" : \"$context.requestId\",\n\
            \      \"resource-path\" : \"$context.resourcePath\",\n      \"http-method\"\
            : \"$context.httpMethod\",\n      \"stage-data\": {\n        #foreach($param\
            \ in $stageVariables.keySet())\n        \"$param\": \"$util.escapeJavaScript($stageVariables.get($param))\"\
            \ #if($foreach.hasNext),#end\n        #end\n      }\n    },\n    \"requestor\"\
            : {\n      \"source-ip\": \"$context.identity.sourceIp\",\n      \"user-agent\"\
            : \"$context.identity.userAgent\",\n      \"account-id\" : \"$context.identity.accountId\"\
            ,\n      \"api-key\" : \"$context.identity.apiKey\",\n      \"caller\"\
            : \"$context.identity.caller\",\n      \"user\": \"$context.identity.user\"\
            ,\n      \"user-arn\" : \"$context.identity.userArn\"\n    },\n    \"\
            request\": {\n      \"querystring\": {\n        #foreach($param in $input.params().querystring.keySet())\n\
            \        \"$param\": \"$util.escapeJavaScript($input.params().querystring.get($param))\"\
            #if($foreach.hasNext),#end\n        #end\n      },\n      \"path\": {\n\
            \        #foreach($param in $input.params().path.keySet())\n        \"\
            $param\": \"$util.escapeJavaScript($input.params().path.get($param))\"\
            \ #if($foreach.hasNext),#end\n        #end\n      },\n      \"header\"\
            : {\n        #foreach($param in $input.params().header.keySet())\n   \
            \     \"$param\": \"$util.escapeJavaScript($input.params().header.get($param))\"\
            \ #if($foreach.hasNext),#end\n        #end\n      },\n      \"body\":\
            \ $input.json('$')\n    }\n  }\n}\n"
        credentials: arn:aws:iam::<snip>:role/<snip>
        type: aws

[gifflen]

Looks good 🚢