Send Threaded Messages

This MR deals with only sending threaded messages. Showing threads will turn up in a follow up. This allows you to start a new thread by clicking reply in thread to a normal message. 

You can also do a threaded reply to a threaded message in the main timeline at the moment because those messages aren't shown in a separate thread timeline yet but will be in future.

src/qml/HoverActions.qml

@@ -105,6 +105,16 @@ QQC2.Control {
                         root.currentRoom.editCache.editId = "";
                         root.focusChatBar();
                     }
+                },
+                Kirigami.Action {
+                    text: i18n("Reply in Thread")
+                    icon.name: "dialog-messages"
+                    onTriggered: {
+                        root.currentRoom.mainCache.replyId = root.delegate.eventId;
+                        root.currentRoom.mainCache.threadId = root.delegate.isThreaded ? root.delegate.threadRoot : root.delegate.eventId;
+                        root.currentRoom.editCache.editId = "";
+                        root.focusChatBar();
+                    }
                 }
             ]
 

src/qml/MessageDelegate.qml

@@ -187,6 +187,10 @@ TimelineDelegate {
      */
     required property var replyMediaInfo
 
+    required property bool isThreaded
+
+    required property string threadRoot
+
     /**
      * @brief Whether this message is replying to another.
      */