[Helm-Chart] Feature: config.yml as ConfigMap & offline-mode

[Nold360]

This feature adds the config.yml-File as a configMap, so it can be modified easier (e.g. we could get rid of the environment variables).

I also implemented a new values parameter offlineMode which will set the offline parameter in config.yml.

[bdsoha]

Looks like this is related to #6057