Check if I still manage linter definitions etc. centrally

[sebastian-sommerfeld-io]

• [x] Are these files still downloaded from a central location?
• [x] If yes, then remove this management because this results on too many obsolete entries for most projects and prohibits some individual layouts (like following the recommended golang package layout).
• [x] Remove all "this is centrally managed" comments from all projects
• [x] Update docs in https://github.com/sommerfeld-io/.github/