Add labels that show what parts of the codebase are touched by a PR

[GeckoEidechse]

This could apply to basically all repos including Wiki and Docs, although Launcher and Mods would obviously be priority

Idea brought up by @Jan200101 on the Northstar Discord

Example:

Controlled by GitHub Action and config file:

Action in question: https://github.com/marketplace/actions/labeler

[GeckoEidechse]

cc @ASpoonPlaysGames as he mentioned also having looked into this in the past