Run command implementation

The next step is to reimplement the SSHKeyInjectingHandler as PseudoCloudInitHandler. The handler should allow:

[x] injecting arbitrary SSH public keys to the authorized keys file, as it does now
[x] injecting the hostname to /etc/hostname file, if setting not empty
[x] injecting arbitrary environment variables to the /etc/profile.d/bootstrap-env.sh file: investigate https://github.com/combust-labs/gotenv
[x] rewrite /etc/hosts to the default value

127.0.0.1   localhost
::1 localhost ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

This will have to updated at a later stage to inject an IPAM allocated VMM IP address but this will require manually allocating the IP and handing it over to the VMM so the VMM knows its own IP.

combust-labs / firebuild

Run command implementation #6