support passing api token in Basic auth password (#12416)

docs/sources/http_api/auth.md

@@ -44,6 +44,14 @@ Authorization: Bearer eyJrIjoiT0tTcG1pUlY2RnVKZTFVaDFsNFZXdE9ZWmNrMkZYbk
 
 The `Authorization` header value should be `Bearer <your api key>`.
 
+The API Token can also be passed as a Basic authorization password with the special username `api_key`:
+
+curl example:
+```bash
+?curl http://api_key:eyJrIjoiT0tTcG1pUlY2RnVKZTFVaDFsNFZXdE9ZWmNrMkZYbk@localhost:3000/api/org
+{"id":1,"name":"Main Org."}
+```
+
 # Auth HTTP resources / actions
 
 ## Api Keys