[x] Clean-up code base, remove static state from the classes.
[x] Unify usage of constantw across platforms.
[x] Persist subscribed topics and notification actions in local preferences.
[x] Refactor project to become more unit-testable, finally add some unit tests.
[x] Add platform initialization for MAUI Android and iOS.
[x] Add queuing for notification events, including persistent queues.
[x] Handle duplicate notifications on Android.
[x] Clean-up code base, remove static state from the classes. [x] Unify usage of constantw across platforms. [x] Persist subscribed topics and notification actions in local preferences. [x] Refactor project to become more unit-testable, finally add some unit tests. [x] Add platform initialization for MAUI Android and iOS. [x] Add queuing for notification events, including persistent queues. [x] Handle duplicate notifications on Android.