🖼 Replaced Dolphin with Nauvis, mime types, image-viewer

- Added Gstreamer packages for audio data
- Replaced catppuccin wallpaper on lockscreen with one where the logo is higher
- Replaced dolphin with nautilus file manager
- Moved Gnome related configs to /gnome
- Added Gnome appindicator and extension manager
- Added loupe and gimp
- Added mime types for image files

gnome/nautilus.nix

@@ -0,0 +1,9 @@
+{ pkgs, ... }:
+# TODO file-preview for videos, svgs and other types
+{
+  environment.systemPackages = with pkgs; [
+    nautilus
+  ];
+
+  programs.nautilus-open-any-terminal.enable = true;
+}