[public-api] Extend k8s definitions with a service

[easyCZ]

Description

Add a k8s service for existing public-api deployment. This will allow the service to be exposed in the Caddy proxy config such that we can route traffic to the deployment (accessible, but still unused), only in preview builds for now.

Related Issue(s)

• Part of Deploy a Hello World server as initial Public API  #9229
• Depends on https://github.com/gitpod-io/gitpod/pull/9324/files

How to test

1. Start a workspace from this branch
2. List k8s services with kubectl get service and observe public-api-service
3. Hit the service:

kubectl exec mysql-0 -it -- /bin/bash

$ curl http://public-api-server:9000
hello world\n

Release Notes

NONE

Documentation

NONE

/hold

[andrew-farries]

Nice 👍 Can hit the service from a pod.

[geropl]

(@andrew-farries please assign yourself as soon as you start reviewing so we avoid double work. Thx! 🙏 )

[easyCZ]

/werft run with-clean-slate-deployment=true

👍 started the job as gitpod-build-mp-papi-service-def.8

[easyCZ]

/unhold

[easyCZ]

/werft run with-clean-slate-deployment=true

👍 started the job as gitpod-build-mp-papi-service-def.9