misc: drop 'new' prefix from model names

src/app/accountadapter.cpp

src/app/accountadapter.h

src/app/audiomanagerlistmodel.cpp

src/app/avadapter.cpp

src/app/avatarregistry.cpp

src/app/calladapter.cpp

src/app/calloverlaymodel.cpp

src/app/currentaccount.cpp

src/app/currentaccounttomigrate.cpp

src/app/deviceitemlistmodel.cpp

src/app/lrcinstance.cpp

src/app/lrcinstance.h

src/app/mediacodeclistmodel.cpp

src/app/qmlregister.cpp

src/app/videodevices.h

src/libclient/CMakeLists.txt

src/libclient/accountmodel.cpp

src/libclient/api/account.h

src/libclient/api/accountmodel.h

src/libclient/api/callmodel.h