minetest: 5.7.0 -> 5.8.0, cleanup
* Inline the generic builder, since we don't build multiple versions
anymore
* Remove unused patches, flags, and overrides
* Remove minetest_game, it has been debundled
* Use finalAttrs
* Use lib.cmake*
* Add a top-level attribute for the touch variant
* Define the server- and client-only variants through overrides in
all-packages.nix
* Move the *_5 aliases to top-level/aliases.nix
* General cleanup
Closes #273207