tests: http_server: add tests for dynamic response context

Add tests covering new method of providing a response for dynamic
resources.

Tests cover the application sending response codes and headers,
overriding "default" headers, and sending various combinations of
headers and body data. Each case is tested for HTTP1 & HTTP2, both POST
and GET methods.

Signed-off-by: Matt Rodgers <mrodgers@witekio.com>
3 files changed