Use special Maven settings with access token to GitHub Packages

Use special Maven settings with access token to GitHub Packages

The access token is for the 'kriegaex' account. Can be adjusted or
extended in order to support other Package registries, too. for now, I
just want to see it this solves the authentication error problems during
GitHub CI builds.

The new file .mvn/settings-read-github-packages.xml contains additional
information and links to online sources, explaining why this is
necessary.

Signed-off-by: Alexander Kriegisch <Alexander@Kriegisch.name>