Removed dependencies from userstatuswwu

[NinaHerrmann]

Removes the subplugin userstatuswwu, which was developed to support the removal of users depending on a .txt file.
The plugin will be archived in another git repository - if future projects aim to develop a similar plugin.
Moreover, the ci test were updated.

[NinaHerrmann]

@ksteitz @my-curiosity
The pull-request removes the dependency from userstatuswwu.
I also made some smaller fixes to the CI Pipeline and Code Style. If any changes are not suitable to you please don't hesitate to tell me!
Cheers!

[my-curiosity]

Hi @NinaHerrmann,
thanks for the PR, it is very helpful. I believe that any possible conflicts with our changes in the tu branch can be easily resolved, so no further changes are needed here.

[NinaHerrmann]

Thank you so much!