Implemented db-to-ldap relations

tests/test_role.py

tests/test_user.py

uffd/ldap.py

uffd/role/models.py

uffd/role/templates/role.html

uffd/role/utils.py

uffd/role/views.py

uffd/user/models.py

uffd/user/templates/user.html

uffd/user/views_user.py