[web] Stop using webconfig.vc_config()
The main issue is that this creates an entirely new Repository object
(since commit 3914388b2d0f) and thus reloads all the cubes, taking for
ever.
Related to #8634417.
usr/lib/python2*/*-packages/cubicweb/server/
usr/lib/python2*/*-packages/cubicweb/hooks/
usr/lib/python2*/*-packages/cubicweb/sobjects/
usr/lib/python2*/*-packages/cubicweb/schemas/
usr/share/cubicweb/migration/