Vagrant defaults to nfs on linux, which requires root rights and changes
nfs configuration. The rsync backend is much less invasive, but needs
manual triggering (at least `vagrant rsync-auto`).
Closes#29
A simple Vagrant VM based on fedora 25 cloud. It syncs `dist` to
`/usr/local/share/cockpit/<dirname>` on the VM.
Also decrease the minimum required version in `manifest.json` to match
the one that's currently in fedora 25.
