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/interfaces/models/mikrotik.py

@@ -1,22 +1,21 @@
 import os
 from oxi.interfaces import register_parser
 from oxi.interfaces.base import BaseDevice
-from oxi.interfaces.contract import Interfaces, System, Vlans
 
 
 @register_parser(["routeros", "ros", "mikrotik"])
 class Mikrotik(BaseDevice):
     template = "mikrotik.ttp"
 
-    def system(self) -> "System":
-        systems = self._raw.get("system")
-        return System(**systems)
+    # def system(self) -> "System":
+    #     systems = self._raw.get("system")
+    #     return System(**systems)
 
-    def interfaces(self) -> "Interfaces":
-        return [Interfaces(**item) for item in self._raw.get("interfaces")]
+    # def interfaces(self) -> "Interfaces":
+    #     return [Interfaces(**item) for item in self._raw.get("interfaces")]
 
-    def vlans(self) -> list["Vlans"]:
-        return [Vlans(**item) for item in self._raw.get("vlans")]
+    # def vlans(self) -> list["Vlans"]:
+    #     return [Vlans(**item) for item in self._raw.get("vlans")]
 
 
 if __name__ == "__main__":