Add support for reporting rooms and users

This was added in recent Matrix versions, and a desperately needed
feature.

src/libneochat/neochatroom.h

@@ -622,6 +622,11 @@ public:
      */
     QString pinnedMessage() const;
 
+    /**
+     * @brief Send a report about this room.
+     */
+    Q_INVOKABLE void report(const QString &reason);
+
 private:
     bool m_visible = false;