Refactor BaseDevice methods for improved data handling and validation

- Updated the `BaseDevice` class to replace `_raw` with `raw` for consistency in data access.
- Enhanced the `vlans`, `interfaces`, and `system` methods to utilize the new `raw` attribute.
- Introduced a `_validate_contract` method to streamline the validation of parsed data into structured models.
- Adjusted the `Keenetic` and `Mikrotik` models to align with the updated data handling approach, ensuring proper parsing and decoding of interface and VLAN data.

oxi/conf.py

@@ -30,7 +30,7 @@ class NodeConfig:
 
     @property
     def json(self):
-        return self._response.json()
+        return self._parsed_data.json()
 
     def __str__(self):
         return self.text