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/dark-mode/methods.ts

@@ -0,0 +1,16 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { store } from '..'
+import type { DarkModeConfigAction, DarkModePreference } from './types'
+import { DarkModeConfigActionType } from './types'
+
+export const setDarkModePreference = (darkModePreference: DarkModePreference): void => {
+  store.dispatch({
+    type: DarkModeConfigActionType.SET_DARK_MODE,
+    darkModePreference
+  } as DarkModeConfigAction)
+}

frontend/src/redux/dark-mode/reducers.ts

@@ -0,0 +1,27 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { Reducer } from 'redux'
+import type { DarkModeConfig, DarkModeConfigAction } from './types'
+import { DarkModeConfigActionType, DarkModePreference } from './types'
+
+const initialState: DarkModeConfig = {
+  darkModePreference: DarkModePreference.AUTO
+}
+
+export const DarkModeConfigReducer: Reducer<DarkModeConfig, DarkModeConfigAction> = (
+  state: DarkModeConfig = initialState,
+  action: DarkModeConfigAction
+) => {
+  switch (action.type) {
+    case DarkModeConfigActionType.SET_DARK_MODE:
+      return {
+        darkModePreference: action.darkModePreference
+      }
+    default:
+      return state
+  }
+}

frontend/src/redux/dark-mode/types.ts

@@ -0,0 +1,23 @@
+/*
+ * SPDX-FileCopyrightText: 2022 The HedgeDoc developers (see AUTHORS file)
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import type { Action } from 'redux'
+
+export enum DarkModeConfigActionType {
+  SET_DARK_MODE = 'dark-mode/set'
+}
+
+export enum DarkModePreference {
+  DARK,
+  LIGHT,
+  AUTO
+}
+
+export interface DarkModeConfig {
+  darkModePreference: DarkModePreference
+}
+
+export type DarkModeConfigAction = Action<DarkModeConfigActionType.SET_DARK_MODE> & DarkModeConfig