mute is now a normal request

src/gui/official/CallManagerImpl.cpp

src/gui/official/CallManagerImpl.hpp

src/gui/official/PhoneLineManagerImpl.cpp

src/gui/official/Request.cpp

src/gui/official/RequesterImpl.cpp

src/gui/official/SFLPhoneApp.cpp

src/gui/official/SFLPhoneWindow.cpp

src/gui/official/SFLRequest.cpp