Eltenger beta for Android publicly available

Very basic feature that should've been there, was probably suggested already at that point.

Actually, when I view something in the mobile app, it does get synchronized on the PC, just not the other way round.

Another update on notifications synchronization: I think the largest step is done, Eltenger itself does detect if a notification has been addressed or not. It just needs to delete the notification if it detects that.