feat: Swagger Connector

[zregvart]

Adds a Initial implementation of a Connector that uses Swagger
specification to invoke REST services.

Fixes #96

[davsclaus]

Ah yeah I can see the problem. You need to determine the headers in the createEndpoint method. And then you have trouble to set those headers before calling the producer.

We have some support for this by using a Processor and set that as setBeforeProducer in the component class. Then this processor will be invoked before the producer. However this processor is shared, and therefore you cannot store local state such as the headers.

So we should make it possible to set a instance of BeforeProducer on the endpoint, so you can do it all from the createEndpoint class.

Then you just set

 Map headers = ... determineHeaders
 endpoint.setBeforeProducer(e -> e.getIn().setHeaders(headers));

[davsclaus]

I logged a ticket: https://issues.apache.org/jira/browse/CAMEL-11975

And there is a commit
apache/camel@ceb8669

Now you can do what I do in that FooComponent in the createEndpoint method of your connector. You should just use setBeforeProducer instead.

[zregvart]

Moved to syndesisio/syndesis#397