auth0: implement identity provider (#1470)

* auth0: implement identity provider

* add auth0 guide

* fix naming

docs/docs/identity-providers/auth0.md

@@ -0,0 +1,32 @@
+---
+title: Auth0
+lang: en-US
+sidebarDepth: 0
+meta:
+  - name: keywords
+    content: auth0
+---
+
+# Auth0
+
+[Log in to your Auth0 account](https://manage.auth0.com/) and head to your dashboard. Select **Applications** on the left menu. On the Applications page, click the **Create Application** button to create a new app.
+
+![Auth0 Applications Dashboard](./img/auth0/dashboard.png)
+
+## Create Regular Web Application
+
+On the **Create New Application** page, select the **Regular Web Application** for your application.
+
+![Auth0 Create Application Select Platform](./img/auth0/create.png)
+
+Next, provide the following information for your application settings:
+
+| Field                        | Description                                                               |
+| ---------------------------- | ------------------------------------------------------------------------- |
+| Name                         | The name of your application.                                             |
+| Application Login URI        | Authenticate URL (e.g. `https://${authenticate_service_url}`)             |
+| Allowed Callback URLs        | Redirect URL (e.g. `https://${authenticate_service_url}/oauth2/callback`).|
+
+Make sure to click **Save Changes** when you're done.
+
+On the same **Settings** page you can copy the **Domain** and use it as the provider url (e.g. `https://dev-xyz.us.auth0.com`), as well as the **Client ID** and **Client Secret**.