It is no longer required to add IP addresses to the Vagrant-generated ssh
configuration because the Vagrant-configured hostnames now match up with the
names morph will try to use to connect to the VMs.

Just require hostName and domain instead of an extra publicIPv4 option.  Leave
behind a similar option, `publicAddress`, just in case it needs to be
overridden at some point, but stop supplying a value for it anywhere.

... clean up 🧹

Less (SLOC) is more

Also configure a new value on the staging grid

Also put library code in a library directory