`clang-tidy`: Introduce new rules

[MonsterDruide1]

So far, clang-tidy is not used on this project. It would allow doing additional styling checks though, we're at least interested in the part that enforces moving constants from initializer-lists into the header.

[MonsterDruide1]

Discord-Discussion about this: https://discord.com/channels/774687602996936747/1353271505273884692