Restructured references section of the docs

docs/source/reference/api-reference/services.auth.md

@@ -0,0 +1,40 @@
+# Services Authentication
+
+## Module: {mod}`jupyterhub.services.auth`
+
+```{eval-rst}
+.. automodule:: jupyterhub.services.auth
+```
+
+### {class}`HubAuth`
+
+```{eval-rst}
+.. autoconfigurable:: HubAuth
+   :members:
+```
+
+### {class}`HubOAuth`
+
+```{eval-rst}
+.. autoconfigurable:: HubOAuth
+   :members:
+```
+
+### {class}`HubAuthenticated`
+
+```{eval-rst}
+.. autoclass:: HubAuthenticated
+   :members:
+```
+
+### {class}`HubOAuthenticated`
+
+```{eval-rst}
+.. autoclass:: HubOAuthenticated
+```
+
+### {class}`HubOAuthCallbackHandler`
+
+```{eval-rst}
+.. autoclass:: HubOAuthCallbackHandler
+```