added btminer get_model and improved return on the rest of the get_models

miners/btminer.py

@@ -6,11 +6,21 @@ from API import APIError
 class BTMiner(BaseMiner):
     def __init__(self, ip: str) -> None:
         api = BTMinerAPI(ip)
+        self.model = None
         super().__init__(ip, api)
 
     def __repr__(self) -> str:
         return f"BTMiner: {str(self.ip)}"
 
+    async def get_model(self):
+        if self.model:
+            return self.model
+        version_data = await self.api.devdetails()
+        if version_data:
+            self.model = version_data["DEVDETAILS"][0]["Model"].split("V")[0]
+            return self.model
+        return None
+
     async def get_hostname(self) -> str:
         try:
             host_data = await self.api.get_miner_info()