feat: support Kafka protocol for functions #876

Job	Run time
integration (integration test, .ci/tests/integration/e2e.yaml)	57m 25s
integration (integration test with oauth2, .ci/tests/integration-oauth2/e2e.yaml)	38m 57s
integration (integration test with downloader, .ci/tests/integration-oauth2/e2e_with_downloader.y...	30m 37s
integration (integration test with tls, .ci/tests/integration/e2e_with_tls.yaml)	39m 0s
	2h 45m 59s

Provide feedback