[web/test] Drop folder cube dependency Copy useful schema bits, define IBreadCrumbs adapter for Folder/fild_under (previously relying on ITree adapter) and adjust unittest_viewselector tests to drop a view that does not exist anymore. Related to #5168939.

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