fix: Move content into to frontend directory

Doing this BEFORE the merge prevents a lot of merge conflicts.

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

frontend/src/redux/application-state.d.ts

@@ -0,0 +1,25 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { OptionalUserState } from './user/types'
+import type { Config } from '../api/config/types'
+import type { EditorConfig } from './editor/types'
+import type { DarkModeConfig } from './dark-mode/types'
+import type { NoteDetails } from './note-details/types/note-details'
+import type { RendererStatus } from './renderer-status/types'
+import type { HistoryEntryWithOrigin } from '../api/history/types'
+import type { RealtimeState } from './realtime/types'
+
+export interface ApplicationState {
+  user: OptionalUserState
+  config: Config
+  history: HistoryEntryWithOrigin[]
+  editorConfig: EditorConfig
+  darkMode: DarkModeConfig
+  noteDetails: NoteDetails
+  rendererStatus: RendererStatus
+  realtime: RealtimeState
+}