[cwctl] fix cubicweb-ctl shell command (closes #2583919) * add an uri parsing utility that documents a bit the uri cubicweb supports out of the box * cwctl: use this utility and refactor a bit for clarity (the novelty here being real support for old style 'myapp', or: * 'inmemory://myapp' * 'pyro://pyro-ns-host:pyro-ns-port/myapp' (pyro access through a pyro concentrator) * 'pyroloc://host:port/pyro-instance-id' (direct access to a pyro repository) * 'zmqpickle-tcp://host:port' * dbapi: refactor to sort out some of the complexity and restore functionality lost in 62213a34726e

debian/tmp/usr/lib/PY_VERSION/site-packages/cubicweb/web usr/lib/PY_VERSION/site-packages/cubicweb
debian/tmp/usr/share/cubicweb/cubes/shared/data usr/share/cubicweb/cubes/shared
debian/tmp/usr/share/cubicweb/cubes/shared/wdoc usr/share/cubicweb/cubes/shared