feat: search options (#540)

* feat: search options

* feat: sanitize folder names

* fix: add cursor: pointer to switch

* fix: explicitly make the search bar a text input

* refactor: remove magic number

* refactor: extract Switch component to its own file

* refactor: split AppState into multiple files

* refactor: review comments

app/assets/javascripts/ui_models/app_state/index.ts

@@ -0,0 +1,6 @@
+export {
+  AppState,
+  AppStateEvent,
+  EventSource,
+  PanelResizedData,
+} from './app_state';