[WIP] Allow reordering of menu icons

[juliushaertl]

This commit enables reordering on the apps menu. A users custom order will be saved inside the browsers local storage.

• [ ] Avoid moving of active app title
• [ ] Apps + button should always be the last icon
• [ ] Add ability to set a default order for new Users
• [ ] Service for storing user and system settings
• [ ] Admin UI to set system order
• [ ] Move from localstorage to user config

[Mannshoch]

Please also add ability to set a default order for new Users

[juliushaertl]

I've moved the development of this feature to an separated app, so that everybody can use the sorting functionality even without direct_menu.

https://github.com/juliushaertl/apporder