Document Python async connection and node sync connections

[prrao87]

People should be aware that we will now provide a Python async and node.js sync (to go with their pre-existing sync/async counterparts) clients, so they can decide what works for their application.

• Python: Add AsyncConnection for asynchronous query execution on Python API kuzu#5061
• Node.js: Implement synchronous APIs for Node.js bindings kuzu#5058

[royi-luo]

Just a heads-up reading from dataframes currently don't work with the Python async API.

For example the following code will give an error Binder exception: Variable df is not in scope.

tab = pa.Table.from_arrays(
        [
            [1, 2, 3],
            ["a", "b", "c"],
            [True, False, None],
        ],
        names=["col1", "col2", "col3"],
    )
result = await conn.execute("LOAD FROM tab RETURN *")

My guess is that this is because async connections execute queries using a separate thread from the calling thread, and thus the dataframe isn't scope for the executing thread. Not sure if there's an easy fix for this but we should document this to start.

[ray6080]

@royi-luo nice catch. I moved this to an issue on main repo kuzudb/kuzu#5139