Populate /etc/hosts with an entry for settings.network.hostname

[zmrow]

Currently we populate/etc/hosts with entries for 127.0.0.1 and ::1 that alias to localhost.

We need to populate it with an entry to alias 127.0.0.1 to the hostname.

One example: For other distros (Ubuntu) CAPI populates this entry in /etc/hosts and kube-vip appears to use /etc/hosts to resolve the hostname.

[zmrow]

We'll definitely need to double check that this doesn't break anything on EC2, but it doesn't seem like it would.

Here's an example of the CAPI code that runs during provisioning:

runcmd:
...
  - "echo \"::1         ipv6-localhost ipv6-loopback\" >/etc/hosts"
  - "echo \"127.0.0.1   localhost\" >>/etc/hosts"
  - "echo \"127.0.0.1   {{ ds.meta_data.hostname }}\" >>/etc/hosts"
...