Add Eltex model and TTP template

- Introduced a new `Eltex` model for parsing Eltex devices.
- Created a corresponding TTP template for Eltex devices, defining required and optional groups for configuration parsing.

oxi/interfaces/models/eltex.py

@@ -0,0 +1,43 @@
+from oxi.interfaces import register_parser
+from oxi.interfaces.base import BaseDevice
+
+
+@register_parser("eltex")
+class Eltex(BaseDevice):
+    template = "eltex.ttp"
+
+    def system(self) -> dict:
+        system = self.raw["system"]
+        serial_num = self.raw["serial"]
+        if serial_num:
+            if len(serial_num) > 1:
+                serial_num = serial_num[0]
+            system["serial_number"] = serial_num.get("serial_number")
+        return system
+
+    def vlans(self) -> list[dict]:
+        vlans_ttp = self.raw.get("vlans", [])
+        vlans = []
+        named_vlan = set()
+        for item in vlans_ttp:
+            if item.get("vlan_id"):
+                named_vlan.add(item.get("vlan_id"))
+                vlans.append(item)
+            else:
+                ids = item.get("vlan_ids", "")
+                tail = item.get("vlan_tail")
+                if tail:
+                    ids = f"{ids},{tail}"
+                for vid in ids:
+                    vid = vid.strip()
+                    if vid in named_vlan:
+                        continue
+                    vlans.append({"vlan_id": vid})
+        return vlans
+
+
+if __name__ == "__main__":
+    with open("./test6.txt") as file:
+        data = file.read()
+    eltex = Eltex(data)
+    print(eltex.parse())