nixos: profiles: move from top-level

My profiles are actually just "special" NixOS modules in that they
orchestrate settings that usually span the NixOS/home-manager boundary,
or otherwise set up configurations from multiple modules at once.

flake/nixos.nix

@@ -14,8 +14,6 @@ let
     }
     # Include generic settings
     "${self}/modules/nixos"
-    # Include bundles of settings
-    "${self}/profiles"
   ];
 
   buildHost = name: system: lib.nixosSystem {

modules/nixos/default.nix

@@ -5,6 +5,7 @@
   imports = [
     ./hardware
     ./home
+    ./profiles
     ./programs
     ./secrets
     ./services