remove enableCors from the config and move it as a job arg

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
move warnings to the job

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)
Merge pull request #3820 from vieux/remove_runtime_from_api

Remove runtime from api