Enable Typescript noImplicitThis (#33250)

- Enable https://www.typescriptlang.org/tsconfig/#noImplicitThis
- Wrap Vue Template-Syntax SFCs in
[`defineComponent`](https://vuejs.org/api/general#definecomponent) which
makes type inference and linter work better
- Move `createApp` calls outside the SFCs into separate files
- Use [`PropType`](https://vuejs.org/api/utility-types#proptype-t) where
appropriate
- Some top-level component properties changed order as dictated by the
linter
- Fix all tsc and lint issues that popped up during these refactors

web_src/js/features/user-settings.ts

@@ -13,7 +13,7 @@ export function initUserSettings() {
 
   initUserSettingsAvatarCropper();
 
-  const usernameInput = document.querySelector('#username');
+  const usernameInput = document.querySelector<HTMLInputElement>('#username');
   if (!usernameInput) return;
   usernameInput.addEventListener('input', function () {
     const prompt = document.querySelector('#name-change-prompt');