gaming improvements

- switched to cachyos-bore kernel from mainline lts kernel
- pinned mesa version at 25 to fix issues with minecraft shaders
- switched steam to use the flatpak, since native steam wouldn't launch with the downgraded mesa version

modules/window-managers/niri.nix

@@ -8,7 +8,6 @@
     inputs.noctalia.packages.${system}.default
     xdg-desktop-portal-gnome
     wl-clipboard
-    wayland-utils
     libsecret
     cage
     wev