MangoWC and Scroll Greeter Support for NixOS (#1647)

* add mangowc greeter to nix.

i am going to be suprised if this only needed this line

* point mangowc to mango

there is no way this works

* mango flake detection and maybe scroll support

* " "

* no mango flake dependency

* mango dependency remove too

i have got to add "parenthesis" to stuff more

* Final De-dependification of MangoWC

it works without the flake YES

* mangowc -> mango pt 1

* mangowc -> mango pt 2

necessary evil. will break inital greetd confs but works after change

* Preserve Compatibility

distro/nix/greeter.nix

@@ -71,6 +71,8 @@ in
         "hyprland"
         "sway"
         "labwc"
+        "mango"
+        "scroll"
       ];
       description = "Compositor to run greeter in";
     };