Fixes : remote provisioning error message, clean friends manager on restart, update contact list when carddav synchro, try to remove ffmpeg

try to remove ffmpeg dependency #LINQT-2015

Clean friends manager maps when restarting app as the linphone core will be reset (fix #LINQT-1933)

only show error message once when linphone restarts if remote configuration failed #LINQT-2030

auto update contact list on carddav synchronized (fix #LINQT-1983)