Add Ubuntu 22.04 box

[geerlingguy]

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.

[fwilhe2]

Hi @geerlingguy

I think based on @rlaun's work this should be possible. I made a draft pr based on both of your code, note that I'm not an expert packer user. Maybe I could contribute a PR if there are no fundamental issues with that approach.