Added strict type checking to the project. (#236)

* Implement strict typing (WIP).

* changes

* Finish type checks

* Fix notification icon, matugen settings and update tsconfig.

* OSD Styling updates and added the ability to configure OSD duration.

customModules/kblayout/layouts.ts

@@ -581,4 +581,4 @@ export const layoutMap = {
     "Wolof": "SN",
     "Yakut": "RU (Sah)",
     "Yoruba": "NG (Yoruba)"
-};
+} as const;