Merge develop into main

Most notable changes:

• CI/CD pipeline
• CUDA implementation of self scattering
• Documentation in rst format

merged

assigned to @sebastian.busch

added 20 commits

• 2ee04ff6...f684353f - 3 commits from branch main
• f684353f...1cc94f7b - 7 earlier commits
• 655eb275 - Additional Documentation for CI
• d284aba1 - Remove old directories and files
• 2fe493e3 - Set locales in docker container
• c171ede4 - Update docker files
• 8deba10d - Remove Nix files
• c0b6959e - Update Docs
• de5980a5 - Make a Link in the Release Item
• f2522eb6 - Mark Release URL as package
• 4ff40515 - Improve CUDA Performance
• 6c7dfc13 - Fix/docu config

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