feat(python): transition Python remote sdk to use Rust implementation (#1701)

* Replaces Python implementation of Remote SDK with Rust one.
* Drops dependency on `attrs` and `cachetools`. Makes `requests` an
optional dependency used only for embeddings feature.
* Adds dependency on `nest-asyncio`. This was required to get hybrid
search working.
* Deprecate `request_thread_pool` parameter. We now use the tokio
threadpool.
* Stop caching the `schema` on a remote table. Schema is mutable and
there's no mechanism in place to invalidate the cache.
* Removed the client-side resolution of the vector column. We should
already be resolving this server-side.

python/python/tests/test_embeddings_slow.py

@@ -18,7 +18,6 @@ import lancedb
 import numpy as np
 import pandas as pd
 import pytest
-import requests
 from lancedb.embeddings import get_registry
 from lancedb.pydantic import LanceModel, Vector
 
@@ -108,6 +107,7 @@ def test_basic_text_embeddings(alias, tmp_path):
 
 @pytest.mark.slow
 def test_openclip(tmp_path):
+    import requests
     from PIL import Image
 
     db = lancedb.connect(tmp_path)