[serverctl] allow to sync multiple and all sources in source-sync command Breaking change: by default source are not synced anymore if it is fresh (regards to synchronization-interval). To get the previous behavior an option --force is added. Closes #13886467

usr/bin/cubicweb-ctl usr/bin/
usr/lib/python2*/*-packages/cubicweb/cwctl.py
../cubicweb-ctl.bash_completion etc/bash_completion.d/cubicweb-ctl