Refactor: Cleanup app removal, remove legacy app list generator and CustomAppsList file support (#662)

* remove support for uninstalling old sunset apps

* Add color legend on app removal screen

* Remove legacy app list generator and custom apps file support
Replaced by GUI config export/import, dynamic RemovalMethod, and
CLI app removal settings saved to LastUsedSettings.json.

* Verify app removal by checking actual installation state instead of trusting winget output

Config/Features.json

@@ -339,18 +339,6 @@
       "MinVersion": null,
       "MaxVersion": null
     },
-    {
-      "FeatureId": "RemoveAppsCustom",
-      "Label": "Remove custom selection of apps",
-      "Category": null,
-      "RegistryKey": null,
-      "ApplyText": "Removing selected apps",
-      "UndoLabel": null,
-      "ApplyUndoText": null,
-      "RegistryUndoKey": null,
-      "MinVersion": null,
-      "MaxVersion": null
-    },
     {
       "FeatureId": "RemoveGamingApps",
       "Label": "Remove the Xbox App and Xbox Gamebar",