Functional push Receive

Receives pushes even when not active.
1. In SimpleRandoLib all initialization takes place in ApplicationSRP.
Strangely "LibManager.setPushCallback(callback)" dont work when
initialized not from Application class. Will figure it out later.
2. New - "PushReceiveCallback" for handling with push notifications.
3. After calling "enablePushNotifications" also current installation
registers to CurrentUser.