Serve Wiki files from within repo

[Zabuzard]

This adds a github action that syncs the contents of our Wiki from within the repo.

Therefore, a new wiki folder was added, with the current Wiki content. The newly added gh-action file wiki-sync.yaml syncs its content to the Wiki on each push to develop.

(also renamed some existing .yml files to .yaml while at it)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-advanced-security]

This pull request sets up GitHub code scanning for this repository. Once the scans have completed and the checks have passed, the analysis results for this pull request branch will appear on this overview. Once you merge this pull request, the 'Security' tab will show more code scanning analysis results (for example, for the default branch). Depending on your configuration and choice of analysis tool, future pull requests will be annotated with code scanning analysis results. For more information about GitHub code scanning, check out the documentation.