feat: add getHttpClient method and deprecate old service proxy

[davidebianchi]

This is an implementation of #185. The next breaking changes should remove the MICROSERVICE_GATEWAY_SERVICE_NAME required env var

This will resolve:

• Allow the proxies functions to receive query parameters as string into the path of the request #44
• Should forward the request id in internal calls  #73
• also getServiceProxy does not return on 204 response and returnAs: 'BUFFER' if using node >= 13.0.0 #104 should be resolved, but it is not possible to reproduce (added a test with the given information, and it passes)
• handle Missing "prefix" parameter in Service creation of getDirectServiceProxyFromUrlString function #203 correctly in the new function
• Default logs in TRACE or DEBUG level #120
• Default parsing of response payload to JSON with statusCode 200 throw error if the payload is empty #222

Checklist

• your branch will not cause merge conflict with master
• run npm test
• tests are included
• the documentation is updated or integrated accordingly with your changes
• the code will follow the lint rules and style of the project
• you are not committing extraneous files or sensible data

[coveralls]

Coverage decreased (-0.1%) to 97.463% when pulling 0b6353b on add-http-client-method into a0a2d60 on master.

[ilteoood]

LGTM

[fredmaggiowski]

Some questions related to the doc, the implementation is fine

[davidebianchi]

Update the PR, add also the isMiaHeaderToProxy option to base options