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/timelinemessagemodel.h

@@ -32,42 +32,6 @@ class TimelineMessageModel : public MessageModel
     QML_ELEMENT
 
 public:
-    /**
-     * @brief Defines the model roles.
-     */
-    enum EventRoles {
-        DelegateTypeRole = Qt::UserRole + 1, /**< The delegate type of the message. */
-        EventIdRole, /**< The matrix event ID of the event. */
-        TimeRole, /**< The timestamp for when the event was sent (as a QDateTime). */
-        SectionRole, /**< The date of the event as a string. */
-        AuthorRole, /**< The author of the event. */
-        HighlightRole, /**< Whether the event should be highlighted. */
-        SpecialMarksRole, /**< Whether the event is hidden or not. */
-        ProgressInfoRole, /**< Progress info when downloading files. */
-        GenericDisplayRole, /**< A generic string based upon the message type. */
-        MediaInfoRole, /**< The media info for the event. */
-
-        ContentModelRole, /**< The MessageContentModel for the event. */
-
-        IsThreadedRole, /**< Whether the message is in a thread. */
-        ThreadRootRole, /**< The Matrix ID of the thread root message, if any . */
-
-        ShowSectionRole, /**< Whether the section header should be shown. */
-
-        ReadMarkersRole, /**< The first 5 other users at the event for read marker tracking. */
-        ShowReadMarkersRole, /**< Whether there are any other user read markers to be shown. */
-        ReactionRole, /**< List model for this event. */
-        ShowReactionsRole, /**< Whether there are any reactions to be shown. */
-
-        VerifiedRole, /**< Whether an encrypted message is sent in a verified session. */
-        AuthorDisplayNameRole, /**< The displayname for the event's sender; for name change events, the old displayname. */
-        IsRedactedRole, /**< Whether an event has been deleted. */
-        IsPendingRole, /**< Whether an event is waiting to be accepted by the server. */
-        IsEditableRole, /**< Whether the event can be edited by the user. */
-        LastRole, // Keep this last
-    };
-    Q_ENUM(EventRoles)
-
     explicit TimelineMessageModel(QObject *parent = nullptr);
 
     /**