cubicweb-condor #2277696 [commands] replace the big string for default params by an extensible data structure [done]

because there are many job options and the current mecanisme is inflexible

prioritynormal
typeenhancement
done in0.2.0
load0.100
load left0.000
closed by#9f4cddde7b81 [commands] provide easy to extend default/initial job parameters (closes #2277696)