Move device files into new folder

src/modules/device/services/Device.ts

@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+export const DEFAULT_DEVICE = 'default';
+
+let activeDevice = DEFAULT_DEVICE;
+export const getActiveDevice = (): string => activeDevice;
+export const setActiveDevice = (device: string) => {
+    activeDevice = device;
+};