Move RootFolderAppState to root AppState

(cherry picked from commit 5e1b46d2aa8d6621db38e6ddb077a8dd591a9aca)

Close #8928

frontend/src/App/State/RootFolderAppState.ts

@@ -0,0 +1,12 @@
+import AppSectionState, {
+  AppSectionDeleteState,
+  AppSectionSaveState,
+} from 'App/State/AppSectionState';
+import RootFolder from 'typings/RootFolder';
+
+interface RootFolderAppState
+  extends AppSectionState<RootFolder>,
+    AppSectionDeleteState,
+    AppSectionSaveState {}
+
+export default RootFolderAppState;