Update project description and enhance documentation for clarity

- Revised the project description in `pyproject.toml` to better reflect the functionality of the `oxipy` client.
- Improved the README.md by adding detailed explanations of the project structure, installation instructions, and usage examples.
- Updated documentation files to enhance clarity and organization, including sections on extending models and writing TTP templates.
- Adjusted various TTP templates to ensure consistency and accuracy in the parsing of device configurations.

oxi/interfaces/models/huawei.py

@@ -6,8 +6,8 @@ from oxi.interfaces.base import BaseDevice
 class Huawei(BaseDevice):
     template = "huawei.ttp"
 
-    def vlans(self):
-        vlan_ids = self.raw["vlans"].get("vlan_ids")
+    def vlans(self) -> list[dict]:
+        vlan_ids = self.raw.get("vlans", {}).get("vlan_ids", [])
         return [{"vlan_id": vlan} for vlan in vlan_ids]