## 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
self.client.logout()
        with self.settings(**MOCK_SETTINGS):
            response = self.client.get("/api/saml/metadata/")
        self.assertEqual(response.status_code, status.HTTP_401_UNAUTHORIZED)
        self.assertEqual(response.json(), self.unauthenticated_response())
    def test_only_admins_can_get_saml_metadata(self):
        with self.settings(**MOCK_SETTINGS):
            response = self.client.get("/api/saml/metadata/")
        self.assertEqual(response.status_code, status.HTTP_403_FORBIDDEN)
        self.assertEqual(
            response.json(),
            self.permission_denied_response("You need to be an administrator or owner to access this resource."),
        )
    
    def test_can_initiate_saml_flow(self):
        with self.settings(**MOCK_SETTINGS):
            response = self.client.get("/login/saml/?idp=posthog_custom")
        self.assertEqual(response.status_code, status.HTTP_302_FOUND)
        
        location = response.headers["Location"]
        self.assertIn("https://idp.hogflix.io/saml?SAMLRequest=", location)
    @freeze_time("2021-08-25T22:09:14.252Z")  
    def test_can_login_with_saml(self):