[cwctl] allow overriding config settings from the command line (closes #5557656) eg. cubicweb-ctl start -p port:8082 myapp to overload the port parameter defined in the all-in-one.conf file.

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