add get public and storage feature

app/schemas/public_ip.py

@@ -0,0 +1,13 @@
+from datetime import datetime
+from typing import Literal
+
+from pydantic import BaseModel
+
+
+PublicIPCheckStatus = Literal["first_seen", "unchanged", "changed", "error"]
+
+
+class PublicIPCheckResponse(BaseModel):
+    status: PublicIPCheckStatus
+    checked_at: datetime
+    changed: bool