Fixes #42 lifecycle events Foreground/Background not being detected and sent properly.
Adds FgBg as a dependency again since iOS/Android have incorrect behaviours when system UI is shown on top of the app. WidgetObserver lifecycle detection is still the default for all other platforms.
Refactors the lifecycle to simplify and remove unused classes.
Refines the solution for App Installed events with shared_preferences to prevent pollution on the context JSON object
Ignores Installed/Updated events on web
chore: I removed Firebase from the example since it's a little bit of hassle to run it as you have to register for firebase. It also brings a lot of dependencies. Let's keep it simple for now.
fix: lifecycle events not sent