feat: Implement polls

lib/utils/matrix_sdk_extensions/filtered_timeline_extension.dart

@@ -16,8 +16,8 @@ extension IsStateExtension on Event {
       // always filter out edit and reaction relationships
       !{RelationshipTypes.edit, RelationshipTypes.reaction}
           .contains(relationshipType) &&
-      // always filter out m.key.* events
-      !type.startsWith('m.key.verification.') &&
+      // always filter out m.key.* and other known but unimportant events
+      !isKnownHiddenStates &&
       // event types to hide: redaction and reaction events
       // if a reaction has been redacted we also want it to be hidden in the timeline
       !{EventTypes.Reaction, EventTypes.Redaction}.contains(type) &&
@@ -39,4 +39,10 @@ extension IsStateExtension on Event {
         EventTypes.RoomCreate,
         EventTypes.RoomTombstone,
       }.contains(type);
+
+  bool get isKnownHiddenStates =>
+      {
+        PollEventContent.responseType,
+      }.contains(type) ||
+      type.startsWith('m.key.verification.');
 }

lib/utils/matrix_sdk_extensions/matrix_locals.dart

@@ -363,4 +363,10 @@ class MatrixLocals extends MatrixLocalizations {
 
   @override
   String get refreshingLastEvent => l10n.loadingPleaseWait;
+
+  @override
+  String startedAPoll(String senderName) => '$senderName started a poll';
+
+  @override
+  String get pollHasBeenEnded => l10n.pollHasBeenEnded;
 }