Media Model

Create a media model for all the media message in the timeline and then setup `NeoChatMaximizeComponent` so that it can use the media model to scroll through all loaded images and video in the current room.

Depends upon libraries/kirigami-addons!105

FEATURE: 467411

src/CMakeLists.txt

@@ -36,6 +36,7 @@ add_library(neochat STATIC
     blurhash.cpp
     blurhashimageprovider.cpp
     models/collapsestateproxymodel.cpp
+    models/mediamessagefiltermodel.cpp
     urlhelper.cpp
     windowcontroller.cpp
     linkpreviewer.cpp