backward compatible for addListener

hotfix symbol: variable FirebaseApp

hold notification when app is bootstrapping

Add deleteEntityToken and getEntityToken methods

Add support for notification actions on iOS

We have to save initial notification action response
in case there isn't registered any FCMNotificationReceived
event handler yet. For example when the app is killed by a user
so JS has to be initialized first. The saved action
response will be sent to JS after first
FCMNotificationReceived event handler registered.

Add Pod paths to header search paths

By adding the pod paths, we ensure that if dependencies (namely React) are installed *only* via Pod and not via direct linking in the project.

Dispatch setApplicationIconBadgeNumber on main thread to prevent runtime warnings