Allow the condition for when messages are automatically marked as read to be configurable.

Title this adds a number of options for when messages should be automatically marked as read for the user to choose from.

![image](/uploads/cef95f8c6c77bfdcabb7a8a309bc1fd2/image.png){width=480 height=262}

src/timeline/models/timelinemessagemodel.h

@@ -48,8 +48,6 @@ private:
     std::optional<std::reference_wrapper<const Quotient::RoomEvent>> getEventForIndex(QModelIndex index) const override;
 
     int rowBelowInserted = -1;
-    bool resetting = false;
-    bool movingEvent = false;
 
     int timelineServerIndex() const override;