Cache First Menu

At Menu.js change the load method with the following one and analyze the database created and the algorithm.

load: async () => {
    // Cache First
    const db = await Menu.openDB();
    if (await db.count('categories') == 0) {
        const data = await API.fetchMenu();
        data.forEach(category => db.add('categories', category));
    }
    Menu.data = await db.getAll('categories');
    Menu.render();
}