## 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
with self.settings(MULTI_TENANCY=False):
            response = self.client.post(
                "/api/signup/", {"first_name": "Jane", "email": "hedgehog2@posthog.com", "password": "notsecure"},
            )
            self.assertEqual(response.status_code, status.HTTP_201_CREATED)
            response = self.client.post(
                "/api/signup/", {"first_name": "Jane", "email": "hedgehog2@posthog.com", "password": "notsecure"},
            )
            self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
            self.assertEqual(
                response.json(),
                {
                    "attr": None,
                    "code": "permission_denied",
                    "detail": "New organizations cannot be created in this instance. Contact your administrator if you"
                    " think this is a mistake.",
                    "type": "authentication_error",
                },
            )
    @pytest.mark.ee
    def test_signup_allowed_on_self_hosted_with_env_var(self):