Split out hosts config deployment

Split out hosts config deployment

This patch moves the hosts configuration into its own deployment.
It will continue to use os-apply-config as something that is
required early on in the bootstrapping (it needs to be
configured before puppet runs for example).

The motivation here is so we can refactor all-nodes-config.yaml to use a
new hiera hook that that avoids os-apply-config entirely.

Change-Id: Ib3e4380f205358b27d22a1102b663cf300b1ed86
Partial-bug: #1596373