Motivation for this change

Add the osu-lazer rythm game to nixpkgs

Issues that need to be resolved

Since there isn't easy way to package dotnet packages I've been relying on this package heavily for reference, but I'm still having some issues with restoring packages. I'm still not quite sure what file I should be parsing to retrieve the nuget package dependencies for osu.

• create-deps.sh doesn't properly parse the names of some packages (as a temp fix I've added them manually)
• running dotnet list osu.sln package > mypackage-restore.log and then ./create-deps.sh mypackage-restore.log > deps.nix creates duplicate nuget package entries in deps.nix
• nix-build -A osu-lazer complains about missing packages

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS linux)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.