WIP: feat!(helm): refactor helm chart

[the-technat]

Hey!

While bringing support for securityContext and volumes I discovered that the values.yaml file looks as it grew historically and could need some refactoring.

So I did some refactorings:

• Group app settings below config key
• Group deployment settings below deployment key
• Fix hardcoded replicaCount
• Fix not working securityContext, volumes (jep it didn't worked with the previous PR)

I'm not sure if this PR is ready to merge yet. I tested most of the values if they are correctly rendered. But one thing I have no idea if it's correct as is is nameOverride and fullNameOverride. Guess I need to invest some more time into this. Or what do you think?

[lucky-sideburn]

Dear @the-technat,

I release a new version of the helm chart with your changes.

Thank you for contributing!