## Is your feature request related to a problem?

We manage around 20 3rd party tools that our internal users can log into using G Suite (part of your enterprise / scale offering). When a user leaves, we need to disable their account. Currently we need to do this in G Suite and then any of the 3rd party tools where password login is still possible.

## Describe the solution you'd like

When a user leaves, we disable their account in G Suite and their account in PostHog becomes disabled too. Essentially, the ability to restrict specific users in PostHog to only be able to login via SSO (defaulting to this setting).

## Describe alternatives you've considered

Manually removing their account, and being the enemy of our IT manager.

## Additional context



#### *Thank you* for your feature request – we love each and every one!

ee/api/test/test_authentication.py
_session.save()
        f = open(os.path.join(CURRENT_FOLDER, "fixtures/saml_login_response"), "r")
        saml_response = f.read()
        f.close()
        user_count = User.objects.count()
        with self.settings(**MOCK_SETTINGS):
            response = self.client.post(
                "/complete/saml/",
                {"SAMLResponse": saml_response, "RelayState": "posthog_custom",},
                format="multipart",
                follow=True,
            )
        self.assertEqual(response.status_code, status.HTTP_200_OK)  
        self.assertRedirects(response, "/")  
        
        self.assertEqual(User.objects.count(), user_count + 1)
        user = cast(User, User.objects.last())
        self.assertEqual(user.first_name, "PostHog")
        self.assertEqual(user.email, "engineering@posthog.com")
        self.assertEqual(user.organization, organization)
        self.assertEqual(user.team, None)  
        self.assertEqual(user.organization_memberships.count(), 1)
        self.assertEqual(
            cast(OrganizationMembership, user.organization_memberships.first()).level,
            OrganizationMembership.Level.MEMBER,
        )
        _session = self.client.session
        self.assertEqual(_session.get("_auth_user_id"), str(user.pk))
    @freeze_time("2021-08-25T22:09:14.252Z")
    def test_can_signup_on_non_whitelisted_domain_with_saml(self):