Test: Added APICAST_SERVICE_FILTER_BY_URL integration test.
Test: Added APICAST_SERVICE_FILTER_BY_URL integration test.

This test validates that the parameter `APICAST_SERVICE_FILTER_BY_URL`
is working correctly across multiple services and the service discarding
is working correctly.

Signed-off-by: Eloy Coto <2a8acc28452926ceac4d9db555411743254cf5f9@gmail.com>

3scale/apicast,3scale/apicast,3scale/apicast,3scale/docker-gateway,3scale/docker-gateway,3scale/apicast