[#3649] Pass emitter as an argument for serialization

sflphone-common/src/account.h

sflphone-common/src/config/serializable.h

sflphone-common/src/config/yamlemitter.cpp

sflphone-common/src/config/yamlemitter.h

sflphone-common/src/iax/iaxaccount.cpp

sflphone-common/src/iax/iaxaccount.h

sflphone-common/src/preferences.cpp

sflphone-common/src/preferences.h

sflphone-common/src/sip/sipaccount.cpp

sflphone-common/src/sip/sipaccount.h