[BUG]: Plane frontend probes connection refused

[kosmoz]

Sometimes, the plane frontend pod starts crashlooping, because the liveness probe does not succeed.

Unfortunately we do not know what causes this, but it can be mitigated by adding an initialDelaySeconds to the liveness and readiness probes. The optimal value for this still has to be determined. 20s works, but less would be ideal as the initial delay prevents the pod from being accessible through the service.