*WIP* feat(health-check): health checks added for each container

[bilalcaliskan]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This PR adds liveness/readiness probes for each possible container in a pod. It will make us ensure that our deployments are healthy all the time. This issue also reopened as a new PR because PR #117 is staled.

Which issue(s) this PR fixes:
Fixes #57

Special notes for your reviewer:
I had to add tcpSocket health probes for signaller port(8090) because application normally opens a single port, without varnish-exporter:

root@kube-httpcache-0:/# netstat -lntpu
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp6       0      0 :::8090                 :::*                    LISTEN      1/kube-httpcache

Also i have no idea how to publish new Helm chart https://helm.mittwald.de Helm repository. I could not examine deeply but i hope current Github actions handle that already.

[mittwald-machine]

There has not been any activity to this pull request in the last 14 days. It will automatically be closed after 7 more days. Remove the stale label to prevent this.