feat: add a basic async python client starting point (#1014)

This changes `lancedb` from a "pure python" setuptools project to a
maturin project and adds a rust lancedb dependency.

The async python client is extremely minimal (only `connect` and
`Connection.table_names` are supported). The purpose of this PR is to
get the infrastructure in place for building out the rest of the async
client.

Although this is not technically a breaking change (no APIs are
changing) it is still a considerable change in the way the wheels are
built because they now include the native shared library.

python/src/lib.rs

@@ -0,0 +1,32 @@
+// Copyright 2024 Lance Developers.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+use connection::{connect, Connection};
+use env_logger::Env;
+use pyo3::{pymodule, types::PyModule, wrap_pyfunction, PyResult, Python};
+
+pub mod connection;
+pub(crate) mod error;
+
+#[pymodule]
+pub fn _lancedb(_py: Python, m: &PyModule) -> PyResult<()> {
+    let env = Env::new()
+        .filter_or("LANCEDB_LOG", "warn")
+        .write_style("LANCEDB_LOG_STYLE");
+    env_logger::init_from_env(env);
+    m.add_class::<Connection>()?;
+    m.add_function(wrap_pyfunction!(connect, m)?)?;
+    m.add("__version__", env!("CARGO_PKG_VERSION"))?;
+    Ok(())
+}