Implemented mfa requirements for RoleGroup

.../bad6fc529510_added_rolegroup_requires_mfa_and_cleanup.py

tests/test_invite.py

tests/test_role.py

tests/test_rolemod.py

uffd/mfa/models.py

uffd/mfa/templates/mfa/auth.html

uffd/mfa/templates/mfa/setup.html

uffd/mfa/views.py

uffd/role/models.py

uffd/role/templates/role/show.html

uffd/role/views.py

uffd/selfservice/templates/selfservice/self.html