In addition to attaching to a ducklake, make it possible to connect directly using duckdb.connect(..)

[turntable-justin]

This would allow some use cases where running the requisite attach/use commands is difficult (e.g. in automated use cases). It would also put ducklake on equal footing to :memory:, .duckdb files, and motherduck as the primary storage backends.

[Mytherin]

This is supported since #201