Support bind function for user-defined scalar functions

[jraymakers]

Support for most of scalar functions was added in #89, but Node Neo needs the C API function duckdb_scalar_function_bind_get_extra_info to make bind functions work; this function is due for release in DuckDB 1.4.0 (in Sept).

[jraymakers]

Also added in 1.4.0: duckdb_scalar_function_set_bind_data_copy. Probably should wire that up.