Display room invitation notification (#735)

* Notifications: Add some extra mappings so we keep the original contents and can pass it later to an UI layer

* Fix notifications not appearing for a room if the app was on that room when it went to background.

* Modernize how we create spannable strings for notifications, remove unneeded dependency

* Remove actions from invite notifications temporarily

* Add `NotificationDrawerManager` interface to be able to clear membership notifications when accepting or rejecting a room invite

* Fix tests

* Add comment to clarify some weird behaviours

* Address review comments

* Set circle shape for `largeBitmap` in message notifications

* Fix no avatar in DM rooms

* Fix rebase issues

* Add invite list pending intent:

- Refactor pending intents.
- Make `DeepLinkData` a sealed interface.
- Fix and add tests.

* Rename `navigate__` functions to `attach__`

* Add an extra test case for the `InviteList` deep link

* Address most review comments.

* Fix rebase issue

* Add fallback notification type, allow dismissing invite notifications.

Fallback notifications have a different underlying type and can be dismissed at will.

* Fix tests

libraries/push/impl/src/main/res/values/localazy.xml

@@ -4,6 +4,7 @@
   <string name="notification_channel_listening_for_events">"Listening for events"</string>
   <string name="notification_channel_noisy">"Noisy notifications"</string>
   <string name="notification_channel_silent">"Silent notifications"</string>
+  <string name="notification_fallback_content">"Notification"</string>
   <string name="notification_inline_reply_failed">"** Failed to send - please open room"</string>
   <string name="notification_invitation_action_join">"Join"</string>
   <string name="notification_invitation_action_reject">"Reject"</string>
@@ -47,6 +48,5 @@
   <string name="push_distributor_background_sync_android">"Background synchronization"</string>
   <string name="push_distributor_firebase_android">"Google Services"</string>
   <string name="push_no_valid_google_play_services_apk_android">"No valid Google Play Services found. Notifications may not work properly."</string>
-  <string name="notification_fallback_content">"Notification"</string>
   <string name="notification_room_action_quick_reply">"Quick reply"</string>
 </resources>