[FIX] web: correctly redirect after database creation

When a database is created, we are not auto-logged in to the new
database anymore because the login passed to the authentication request
is 'admin' instead of the one set in the creation form.

To fix this issue, we used the login parameter from the creation form
in the authentication request. We also set the login field to
required in the create database form view.

This bug comes from rev https://github.com/odoo/odoo/commit/903733a32