[authentification] add messages export scope

Author: capcom6

docs/integration/authentication.md

@@ -173,11 +173,12 @@ All scopes follow the pattern: `resource:action`
 
 #### Messages API
 
-| Endpoint                    | Method | Required Scope  | Description         |
-| --------------------------- | ------ | --------------- | ------------------- |
-| `/3rdparty/v1/messages`     | GET    | `messages:list` | List messages       |
-| `/3rdparty/v1/messages`     | POST   | `messages:send` | Send a new message  |
-| `/3rdparty/v1/messages/:id` | GET    | `messages:read` | Get message details |
+| Endpoint                             | Method | Required Scope    | Description         |
+| ------------------------------------ | ------ | ----------------- | ------------------- |
+| `/3rdparty/v1/messages`              | GET    | `messages:list`   | List messages       |
+| `/3rdparty/v1/messages`              | POST   | `messages:send`   | Send a new message  |
+| `/3rdparty/v1/messages/:id`          | GET    | `messages:read`   | Get message details |
+| `/3rdparty/v1/messages/inbox/export` | POST   | `messages:export` | Export messages     |
 
 #### Devices API