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/h3c.py

@@ -6,15 +6,17 @@ class H3C(BaseDevice):
     template = "h3c.ttp"
 
     def vlans(self) -> list[dict]:
-        vlan_list = self.raw["vlans"]
-        vlans = []
+        vlan_list = self.raw.get("vlans", [])
+        vlans: list[dict] = []
         for item in vlan_list:
-            if item.get("vlans_id"):
-                vlans.extend([{'vlan_id': vln }for vln in item.get("vlans_id")])
-            else:
+            vlan_ids = item.get("vlans_id")
+            if not vlan_ids:
                 vlans.append(item)
+                continue
+            vlans.extend({"vlan_id": vlan_id} for vlan_id in vlan_ids)
         return vlans
 
+
 if __name__ == "__main__":
     with open("./test5.txt") as file:
         data = file.read()