Python package improvements

Added an endpoint for getting the actual stored responses, and used it to test and improve the python package.

client-libs/python/openpipe/openpipe_meta.py

@@ -0,0 +1,7 @@
+from attr import dataclass
+
+
+@dataclass
+class OpenPipeMeta:
+    # Cache status. One of 'HIT', 'MISS', 'SKIP'
+    cache_status: str