Reduce CI artifact retention to 1 hour

See merge request !5

update link following crate renaming

See merge request !3

Make the script copy a few useful static files to the output

See merge request !2

Eventually we'll probably want to have a better tool here, but this
will make the site navigable for now.

document private items for Arti

Closes arti#140

See merge request !1

See: tor#40401