## 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!

posthog/api/test/test_signup.py
new_org = Organization.objects.create(name="Hogflix Movies", domain_whitelist=["hogflix.posthog.com"])
        new_project = Team.objects.create(organization=new_org, name="My First Project")
        user_count = User.objects.count()
        response = self.client.get(reverse("social:begin", kwargs={"backend": "google-oauth2"}))
        self.assertEqual(response.status_code, 302)
        url = reverse("social:complete", kwargs={"backend": "google-oauth2"})
        url += f"?code=2&state={response.client.session['google-oauth2_state']}"
        mock_request.return_value.json.return_value = {"access_token": "123", "email": "jane@hogflix.posthog.com"}
        response = self.client.get(url, 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.email, "jane@hogflix.posthog.com")
        self.assertEqual(user.organization, new_org)
        self.assertEqual(user.team, new_project)
        self.assertEqual(user.organization_memberships.count(), 1)
        self.assertEqual(
            cast(OrganizationMembership, user.organization_memberships.first()).level,
            OrganizationMembership.Level.MEMBER,
        )
    @mock.patch("social_core.backends.base.BaseAuth.request")
    @pytest.mark.ee
    def test_social_signup_to_existing_org_with_whitelisted_domains_is_disabled_in_cloud(self, mock_request):