Move core files into new folder

src/lib/DefaultPromiseErrorHandler.ts

@@ -0,0 +1,16 @@
+/*
+ * 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 defaultPromiseErrorHandler = (name: string) => (error: any) => {
+    if (process.env.NODE_ENV === 'production') {
+        return;
+    }
+
+    // eslint-disable-next-line no-console
+    console.error(`${name} failed due to`, error);
+};