Make the ansible install instructions clearer

Change-Id: Ied32f09ff9f136843901e6d97e8aaed733edc9db
Fix for seeds.rb values

Earlier versions of openstack-foreman-installer/astapor required passing
environment variables that would then get replaced in seeds.rb. This is
no longer the case, so a general method of replacing values in seeds.rb
was created, and a number of sane defaults were created.

Change-Id: I0777a47c57cfda03b59eda0888fea883f8e27407
Reload facts when network is restarted

When the network restarts, trigger a reload of facts, to pick up new IP
addresses.

Change-Id: Ifd7ab3cc121d8dd8be3cdfb4dfb7b23a94fd6468