text: Title: Is documentation correct about OIDC_ISS_ENDPOINT?
  Body: The [OIDC_ISS_ENDPOINT](https://django-oauth-toolkit.readthedocs.io/en/latest/settings.html#oidc-iss-endpoint) documentation states that discovery is at `OIDC_ISS_ENDPOINT + /.well-known/openid-configuration/`. That would indicate that one should include the mount point of the `oauth2_provider.urls` right?
  
  But `ConnectDiscoveryInfoView` uses `reverse` to get the path of the  `oauth2_provider:authorize`, `oauth2_provider:token`, `oauth2_provider:user-info`, `oauth2_provider:jwks-info` which results in the doubling of the mount point info.
  
  So a if `oauth2_provider.urls` is mounted at `/some-initial-path/o` all the endpoints, except `issuer`, included in the response has doubled the mount point information. So if the `OIDC_ISS_ENDPOINT` is `http://localhost:8001/some-initial-path/o` the issuer will be `http://localhost:8001/some-initial-path/o` but `authorization_endpoint` will be `http://localhost:8001/some-initial-path/o/some-initial-path/o/authorize/`. Same pattern for `token_endpoint`, `userinfo_endpoint`, and `jwks_uri` 
  
  Looking at the tests, there seems to be a little ambivalence about the topic. See below
  https://github.com/jazzband/django-oauth-toolkit/blob/9d2aac2480b2a1875eb52612661992f73606bade/tests/test_oidc_views.py#L15
  
  `test_get_connect_discovery_info` expects a url without a path and `test_get_connect_discovery_info_without_issuer_url` expects a url with a path `/o` (the default `oauth2` path?).
  
  Anyways - I'm confused. Can anyone clarify if `OIDC_ISS_ENDPOINT` should just be the root url of the Django app or if it should include the mount point of the `oauth2_provider.urls`?
  
  EDIT:
  It looks as if the OIDC specification mentions [this](https://openid.net/specs/openid-connect-discovery-1_0.html#ProviderConfig). The correct pattern should follow the `django_oauth_toolkit` documentation. So `OIDC_ISS_ENDPOINT ` + `/.well-known/openid-configuration` should resolve.
  If this is true, then the test `test_get_connect_discovery_info` should expect `http://localhost/o` instead of `http://localhost` as `issuer` - I think.
  
  EDIT2:
  If `OIDC_ISS_ENDPOINT ` is defined, couldn't it be located somewhere else (another domain) than where `ConnectDiscoveryInfoView` is located? If yes, isn't it then a mistake to base the location of `authorization_endpoint`, `token_endpoint`, `userinfo_endpoint`, and `jwks_uri` on the use of `reverse` for the url patterns on the same host where `ConnectDiscoveryInfoView` is located.
  Why not just hardcode the endpoints to `OIDC_ISS_ENDPOINT` + `{/authorize/, /token/, /userinfo/, o/.well-known/jwks.json}`?
  Or urlparse `OIDC_ISS_ENDPOINT` and use the scheme + netloc + reverse of all the endpoints to fill the output of `ConnectDiscoveryInfoView`. 