Update digitalocean vendor-data

The vendor-data provided here was initially pulled from the default
Fedora cloud.cfg.  Important bits we've modified here:

- We explicitly disable the growpart module, since we're already
taking care of that.
- We allow logins directly to the root account to keep aligned
with our offering, and remove the fedora user account.
- We ensure we're properly managing the hostname and /etc/hosts
as expected when the droplet is first instantiated.
- We've also removed some unnecessary configuration options to
keep it as minimal as possible.