Add generic adapter capability model

dns_sync/npm_client.py

@@ -135,13 +135,3 @@ class NpmClient:
             )
 
         return data
-
-    def certificates(self) -> list[dict[str, Any]]:
-        data = self.get_json("/nginx/certificates")
-
-        if not isinstance(data, list):
-            raise RuntimeError(
-                "NPM certificate response was not a list"
-            )
-
-        return data