feat: use rest namespace for lancedb java sdk (#2845)

After the refactoring on both client and server side, we should have the
ability to fully use lance REST namespace to call into LanceDB cloud and
enterprise. We can avoid having a JNI implementation (which today does
not really do anything except for vending a connection object), and just
use lance-core's RestNamespace.

We will at this moment have a LanceDbRestNamespaceBuilder to allow users
to more easily build the RestNamespace to talk to LanceDB Cloud or
Enterprise endpoint.

In the future, we could extend this further to also support the local
mode through DirectoryNamespace. That will be a separated PR.

docs/mkdocs.yml

@@ -123,6 +123,7 @@ nav:
       - Overview: index.md
       - Python: python/python.md
       - Javascript/TypeScript: js/globals.md
+      - Java: java/java.md
       - Rust: https://docs.rs/lancedb/latest/lancedb/index.html
 
 extra_css: