PR - Adding Multiuser Support

[androidseb25]

This PR is to follow the development of the multiuser support for the container

Priority Changes:

• Removed ENV Variable for Client Token & Gotify Server
• implementation of devices are setuped over the App in the future
• added a user database for the container with all needed informations (Client TOken of device, NTFY-DEVICE Token and Gotify URL)
• !!Gotify Server must be available in network or over public domain for setup!!

Questions please in following Issue #34