The icon comes from "Smoothicons 7" by Corey Marion which I found
as a royalty free icon searching the internet. I would love to
have a purpose built icon, but this is sufficient for now.
The install script sets up a macOS application bundle that references
the generated wezterm binary and the icon. The same technique could
be used to generate a .desktop file for linux.
I've changed the default-prog on macos to be `login -pf $USER` as
that is a better default experience on macOS.
