sources/oauth: Add Mailcow oauth source (#2380)

* Feat: Add Mailcow oauth source

* Feat: Add mailcow icon

* Run make

* Feat: Add tests

* Fix: Remainder from discord test

* Docs: Add mailcow oauth source docs

* Docs: add mailcow source to menu

* Fix: Mailcow provider type in test

* Fix: Formatting

* Fix: Doc file name

website/integrations/sources/mailcow/index.md

@@ -0,0 +1,52 @@
+---
+title: Mailcow
+---
+
+Allows users to authenticate using their Mailcow credentials
+
+## Preparation
+
+The following placeholders will be used:
+
+- `authentik.company` is the FQDN of the authentik install.
+- `mailcow.company` is the FQDN of the mailcow install.
+
+## Mailcow
+
+1. Log into mailcow as an admin and navigate to the OAuth2 Apps settings 
+
+![OAuth2 Apps menu](mailcow1.png)
+
+2. Click "Add OAuth2 Client"
+
+3. Insert the redirect URL: `https://authentik.company/source/oauth/callback/mailcow`
+
+![Add OAuth2 CLient](mailcow2.png)
+
+4. Copy the **Client ID** and **Client secret** and _save it for later_
+
+![ClientID and Secret](mailcow3.png)
+
+## Authentik
+
+5. Under _Directory -> Federation & Social login_ Click **Create > Mailcow OAuth Source**
+
+![Mailcow OAuth Source](mailcow4.png)
+
+6. **Name:** Choose a name (For the example I used Mailcow)
+7. **Slug:** mailcow (You can choose a different slug, if you do you will need to update the Mailcow redirect URL and point it to the correct slug.)
+8. **Consumer Key:** Client ID from step 4
+9. **Consumer Secret:** Client Secret from step 4
+10. **Authorization URL:** https://mailcow.company/oauth/authorize
+11. **Access token URL:** https://mailcow.company/oauth/token
+12. **Profile URL:** https://mailcow.company/oauth/profile
+
+Here is an example of a complete authentik Mailcow OAuth Source
+
+![Example Screen](mailcow5.png)
+
+Save, and you now have Mailcow as a source.
+
+:::note
+For more details on how-to have the new source display on the Login Page see [here](../).
+:::