Package ubuntu is a VPS deploy driver for togo deploy targeting Ubuntu hosts.
It builds a linux/amd64 binary locally, rsyncs it to the host over SSH, writes a
systemd unit, and (re)starts the service. Select with DEPLOY_PROVIDER=ubuntu.
deploy-centos and deploy-debian are sibling drivers with the same flow; they
differ only in the package manager used to install runtime prerequisites.
New returns a generic SSH/systemd VPS driver. distro is the name; pkgInstall is
the shell snippet that installs runtime prerequisites (apt/yum/dnf). Exported so
deploy-centos / deploy-debian can reuse it.