Implemented Wallpaper Selector and Matugen's Wallpaper based auto-theming. (#73)

* Implement matugen - WIP

* Added matugen

* Add types and cleanup code

* Matugen implementation updates and added more options such as scheme and contrast.

* Code cleanup and matugen settings renamed for clarity.

* Makon maroon a primary matugen color.

* Updates to handle variations of matugen colors

* Finalizing matugen and wrapping up variations.

* Minor styling updates of the settings dialog.

* Do a swww dependency check.

* Dependency logic update

* Switch shouldn't double trigger notifications now when checking dependency.

* Logic was inverted

* Add matugen to dependency checker.

* Fixed dependency checking conditional

* Update dependency list in readme and check for matugen before doing matugen operations

* Styling fixes

* OSD Fix

* Remove unused code from wallpaper service.

* Color fixes for matugen.

* Nix updates for new dependencies

* Change default wallpaper to empty.

* Added custom notification service for startup, cleaned up code and updated readme.

scss/style/menus/network.scss

@@ -108,6 +108,7 @@
   }
 
   .menu-icon-button.network.disconnect {
+    color: if($bar-menus-monochrome, $bar-menus-iconbuttons-passive, $bar-menus-menu-network-iconbuttons-passive);
     margin: 0em;
     margin-top: -0.2em;
     margin-left: 1em;