Feature/decoupling app fe to common code

Here we want to decouple the logic for app and app-fe.

We discussed with the team the following principles:

• Any shared code will be completely decouplued with a copy for each jobs/file in the respective pipelines
• Any shared code that is focused on a single task will be extracted into a bash function with clear input and output
• Any business logic that is there for the job itself to do something will be either duplicated or extracted if possible, there could be extracted and extended as script
• We will only use the !reference gitlab approach
• We will use bash function where we cluster some logic which does something specific, and try to keep extends of scripts only when an entire script is extended

To mention Business bash logic has not been fully dried up the main reason is that the effort in drying up logic that might aswell diverge in the near future, didn't hold any real strategic benefit.

The real benefit would have been in a code improvement maybe, but that was out of scope. So I tried to stick to what seamed to be functions that could be "pure" functions trying to achieve something rather than business logic that might repeat across similar jobs