Add CLI show command

[MarcSkovMadsen]

The GraphicWalker is quite powerful. Please add a CLI command for quickly exploring a .csv or .parquet file.

gw show my_data.parquet

Should then start a server on a port. The user can click the link and open in a browser.

gw show my_data.parquet --show

This should also open the browser for the user.

It should be possible to specify a url or s3 bucket instead of a file path.

[MarcSkovMadsen]

Would be nice if someone similarly developed a VS Code extension and a jupyterlab extension. They could provide something unique.