Add Ubuntu 22.04 box

I'd like to add an Ubuntu 22.04 base box, though I'm not sure when I'll get around to it. Since #52 is still not complete (though there's been a lot of movement and something might work for it now...), this could require a little extra work besides just cloning the 20.04 build configuration.

Start by comparing the existing Ubuntu 20.04 build configuration with the requirements for an Ubuntu 22.04 base box. Review issue #52 first, since its incomplete work may affect the implementation. Done means the Ubuntu 22.04 box builds successfully with any additional changes that dependency requires.

Written by the indexing model from the issue text.