[login] split authentication logic from post authentication logic (closes #2200755) * The Session manager is now only in charge of providing a valid session. * LoginControllers are now used in all case but wrong credential. * The LoginControllers are in charge of redirecting the user to the page wanted to see in the first place, expected to see. * The login form is now always submitted to the login controller with an extra argument pointing to the url we should redirect too after successful authentication. The ``"log out first logic"`` logic on login controller is removed because: 1. Other web actor do not do that. 2. Removed code do not need to be reimplemented. 3. We can only get it to work again in a single case: use do a GET request on http://www.my-cw-stuff.io/login 4. I do not see it's purpose.

# -*- 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 repository side views, usually for notification"""