Enable trust anchor injection

Enable trust anchor injection

This commit enables the injection of a trust anchor or root
certificate into every node in the overcloud. This is in case that the
TLS certificates for the controllers are signed with a self-signed CA
or if the deployer would like to inject a relevant root certificate
for other purposes. In this case the other nodes might need to have
the root certificate in their trust chain in order to do proper
validation

Change-Id: Ia45180fe0bb979cf12d19f039dbfd22e26fb4856