[add] Python client packaging first draft

client/src/ledger_app_clients/ethereum/response_parser.py

@@ -0,0 +1,14 @@
+def signature(data: bytes) -> tuple[bytes, bytes, bytes]:
+    assert len(data) == (1 + 32 + 32)
+
+    v = data[0:1]
+    data = data[1:]
+    r = data[0:32]
+    data = data[32:]
+    s = data[0:32]
+
+    return v, r, s
+
+def challenge(data: bytes) -> int:
+    assert len(data) == 4
+    return int.from_bytes(data, "big")