packaging: Move layers from dependencies to components

This makes it easier to implement batch overriding for the components.

(cherry picked from commit cca01407a7)

flake.nix

@@ -165,6 +165,8 @@
                 f = import ./packaging/components.nix {
                   inherit (final) lib;
                   inherit officialRelease;
+                  inherit stdenv;
+                  pkgs = final;
                   src = self;
                 };
               };