Merge pull request #648 from Nheko-Reborn/stickers2

CMakeLists.txt

resources/icons/ui/sticky-note-solid.svg

resources/qml/MatrixText.qml

resources/qml/MessageInput.qml

resources/qml/MessageView.qml

resources/qml/emoji/EmojiButton.qml

resources/qml/emoji/StickerPicker.qml

resources/res.qrc

src/Cache.cpp

src/CacheStructs.h

src/Cache_p.h

src/ImagePackModel.cpp

src/ImagePackModel.h

src/timeline/InputBar.cpp

src/timeline/InputBar.h

src/timeline/TimelineModel.cpp

src/timeline/TimelineModel.h

src/timeline/TimelineViewManager.cpp