ChatCache

Move the functionality to cache the contents of a chat bar from the room directly and to a new ChatCache object. This works pretty much the same with a few extra check and balances, this also made it easy to put a test suite around the functionality so I did. The current functionality should be identical to what exists.

This is in prep for threads which will require managing even more caches if we create one per thread.

src/CMakeLists.txt

@@ -135,6 +135,8 @@ add_library(neochat STATIC
     enums/delegatetype.h
     roomlastmessageprovider.cpp
     roomlastmessageprovider.h
+    chatbarcache.cpp
+    chatbarcache.h
 )
 
 qt_add_qml_module(neochat URI org.kde.neochat NO_PLUGIN