Add backend for new room creation dialogs

CMakeLists.txt

io.github.NhekoReborn.Nheko.yaml

resources/qml/dialogs/CreateDirect.qml

resources/qml/dialogs/CreateRoom.qml

src/ChatPage.cpp

src/ChatPage.h

src/MainWindow.cpp

src/MainWindow.h

src/dialogs/CreateRoom.cpp

src/dialogs/CreateRoom.h

src/ui/NhekoGlobalObject.cpp

src/ui/NhekoGlobalObject.h

src/ui/UserProfile.cpp

src/ui/UserProfile.h