feat: add fastify helpers

[rafaelcr]

Add Fastify helpers that enables us to:

• Create Fastify servers with CORS and Metrics pre-configured
• Generate OpenAPI JSON/YAML specs with standard settings

OpenAPI can be generated from APIs like this:

import { generateOpenApiSpec, logger } from '@hirosystems/api-toolkit';
import { Api } from '../src/api/init';
import { OpenApiSchemaOptions } from '../src/api/schemas';

generateOpenApiSpec({
  apiDefinition: Api,
  prefix: '/ordinals/v1',
  swaggerOptions: OpenApiSchemaOptions,
}).catch(err => logger.error(err));

Closes #3

[csgui]

LGTM 🚀

[blockstack-devops]

🎉 This PR is included in version 1.2.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

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