Experimental blurhash implementation (MXC2448)

CMakeLists.txt

resources/qml/delegates/ImageMessage.qml

src/BlurhashProvider.cpp

src/BlurhashProvider.h

src/ChatPage.cpp

src/ChatPage.h

src/EventAccessors.cpp

src/EventAccessors.h

src/timeline/TimelineModel.cpp

src/timeline/TimelineModel.h

src/timeline/TimelineViewManager.cpp

src/timeline/TimelineViewManager.h

third_party/blurhash/LICENSE

third_party/blurhash/blurhash.cpp

third_party/blurhash/blurhash.hpp