Support voice calls

CMakeLists.txt

resources/langs/nheko_en.ts

resources/media/callend.mp3

resources/media/callend.ogg

resources/media/ring.mp3

resources/media/ring.ogg

resources/media/ringback.mp3

resources/media/ringback.ogg

resources/qml/delegates/MessageDelegate.qml

resources/res.qrc

src/ActiveCallBar.cpp

src/ActiveCallBar.h

src/Cache.cpp

src/CallManager.cpp

src/CallManager.h

src/ChatPage.cpp

src/ChatPage.h

src/TextInputWidget.cpp

src/TextInputWidget.h

src/UserSettingsPage.cpp