Add HEAD request method to Data Service REST Job Configuration

QA:

Create rest job with only HEAD method allowed, publish it and enable it as Data App. Try to run the data app using Run App button and check the message that it ran successful but without body. Try to invoke it using data service URL - only HEAD method should return success other methods should return "405 - method not allowed".

Create rest job with HEAD and GET methods allowed, publish it. Invoke it using data service URL with HEAD method and check that it does not return the body. Invoke it with GET method and check the body is present. Compare response headers for HEAD and GET - for small responses it should be the same. For large responses (not sure how large - hunderds of MB maybe) the GET response may contain extra header "Transfer-Encoding: chunked" and missing "Content-Length" header - this is ok. Otherwise the headers should be the same.

Create custom headers in rest job graph (using CTL function setResponseHeader) with HEAD method allowed and check they are part of response headers when the HEAD method is used to invoke the service.

Sprint to Blue set.