download official Fedora CoreOS (fcos) files and start a xhyve or hyperkit vm

This thrown together repo by default loads a ignition config from my web server and loads my private key. So definitely change ignition_url in settings.json.

• Every boot generates new SSH host keys.
• copy settings.json to ~/.config/xhyve_fcos.json for the script to accept configuration.
• On my laptop it works with xhyve and hyperkit (which comes with docker desktop). YMMV.
• Load fcct, the fcc to ign transpiler, from the official repo
• ./fcct --pretty --strict < default.fcc > default.ign
• Copy default.ign to a web server, and insert the url into settings.json
• Recycling the UUID should result in the same IP. Should.

• accept command line arguments which override settings from settings.json
• find a way to make a configuration persistent (save uuid in a useful way).
• run fcct automatically
• enable persistence (disk images)
• maybe use sqlite which could track UUIDs, corresponding disk images and vm-names (vm-names as cli arguments to select entries from the db)
• start a webserver that delivers the default.ign file