[server] refactor cleanup() code used by "cubicweb-ctl delete"
Try to make each logical step (i.e. "delete database" and "delete user")
a bit more visible and explicit.
This is a preparatory work to easily plug the "delete namespace" feature.
from cubicweb.schemas.base import in_group, CWSourceSchemaConfig
# copy __permissions__ to avoid modifying a shared dictionary
in_group.__permissions__ = in_group.__permissions__.copy()
in_group.__permissions__['read'] = ('managers',)
cw_for_source = CWSourceSchemaConfig.get_relation('cw_for_source')
cw_for_source.__permissions__ = {'read': ('managers', 'users'),
'add': ('managers',),
'delete': ('managers',)}