Optimize executions by filtering changelist

[devtobi]

Is your feature request related to a problem? Please describe.
Currently a lot of workflows and action runs are inrrelevant for PRs (e.g. building a backend when only changes in an EAI where made)

Describe the solution you'd like
Reuse the path-filter action introduced in #25 for other workflows as well

[hupling]

theoretisch kann man das mit https://docs.github.com/en/actions/writing-workflows/workflow-syntax-for-github-actions#onpushpull_requestpull_request_targetpathspaths-ignore einstellen, aber dann muss man das alles wieder einzeln angeben, weil man keine Variablen verwenden kann.