Create room threads list view (#6904)

Implement https://github.com/vector-im/element-web/issues/18957 following requirements:
* Create a new right panel view to list all the threads in a given room.
* Change ThreadView previous phase to be ThreadPanel rather than RoomSummary
* Implement local filters for My and All threads

In addition: 
* Create a new TileShape for proper rendering requirements (hiding typing indicator)
* Create new timelineRenderingType for proper rendering requirements

res/css/structures/_RightPanel.scss

@@ -79,6 +79,10 @@ limitations under the License.
     }
 }
 
+.mx_RightPanel_threadsButton::before {
+    mask-image: url('$(res)/img/element-icons/room/thread.svg');
+}
+
 .mx_RightPanel_notifsButton::before {
     mask-image: url('$(res)/img/element-icons/notifications.svg');
     mask-position: center;