Summary:
Login system using a custom authentication backend hitting on auth.eistiens.net
Base for account Model, and first templates.

Test Plan:
    - Create & source the venv, install the requirements
    - Migrate the changes
    - Create the ldap_login.json file with LDAP credentials in it, like in the example file
    - Run manage.py test

Reviewers: caubin, Valz, Thooms

Reviewed By: Valz, Thooms

Maniphest Tasks: T12

Differential Revision: http://phabricator.atilla.org/D7