move some gaming packages to inbuild settings; manage git config declaritively

modules/gaming.nix

@@ -9,8 +9,10 @@
     remotePlay.openFirewall = true; # Open ports in the firewall for Steam Remote Play
     dedicatedServer.openFirewall = true; # Open ports in the firewall for Source Dedicated Server
     #gamescopeSession.enable = true;
+    protontricks.enable = true;
   };
   programs.gamemode.enable = true;
+  programs.gamescope.enable = true;
 
   # ensure users who need access to this have `cdrom` as `extraGroups`
   programs.cdemu.enable = true;