cubicweb #5557656 allow to overload a configuration parameter by an cmdline option when starting an instance [validation pending]

something like:

cubicweb-ctl start -p port=9090 myapp
prioritynormal
typeenhancement
done in3.21.0
load0.500
load left0.000
closed by#1dcc52f5e340 [cwctl] allow overriding config settings from the command line (closes #5557656)
patch[cwctl] allow to override config parameters as cmdline options when starting an instance (closes #5557656) [applied]