[server/test] stop using email cube - make unittest_migractions use a separate datadir, and add a fake email cube there (we use it to test {add,drop}_cube, so need something that looks like a cube) - for the other test modules, just copy what we need from cubicweb-email's schema to our test schema

# -*- coding: utf-8 -*-
# copyright %(year)s %(author)s, all rights reserved.
# contact %(author-web-site)s -- mailto:%(author-email)s
#
%(long-license)s
"""%(distname)s views/forms/actions/components for web ui"""