cubicweb #14127941 skeleton subdirectories are not installed [validation pending]

python setup.py install installs an empty skeleton directory in lib/python2.7/site-packages/cubicweb, therefore breaking the cubicweb-ctl newcube command.

priorityimportant
typebug
done in3.23.2
load left0.000
closed by#63ac20ef558e [pkg] Properly export data files in setup.py and adjust "newcube" test
patch[pkg] Properly export data files in setup.py and adjust "newcube" test [rejected][pkg] Properly export data files in setup.py and adjust "newcube" test [applied]