Move the reaction delegate into the bubble

Move the reaction delegate into the bubble so it can be instantiated by the Content model. This aims to make sure we only instantiate it when needed rather than for every event. You can now hover the event to show the ReactionComponent with a button to add a reaction if none are currently present

Added bonus ReactionModel no longer needs an event pointer, the event ID is enough to get reaction from the room so things are less likely to blow up.

src/models/threadmodel.h

@@ -19,7 +19,6 @@
 #include "messagecontentmodel.h"
 
 class NeoChatRoom;
-class ReactionModel;
 
 /**
  * @class ThreadFetchModel
@@ -172,8 +171,6 @@ private:
     ThreadFetchModel *m_threadFetchModel;
     ThreadChatBarModel *m_threadChatBarModel;
 
-    QMap<QString, QSharedPointer<ReactionModel>> m_reactionModels;
-
     QPointer<Quotient::GetRelatingEventsWithRelTypeJob> m_currentJob = nullptr;
     std::optional<QString> m_nextBatch = QString();
     bool m_addingPending = false;