Redeploy cinder/compute nodes if new controller added

Addition of new controller affects cluster messaging,
particularly cinder/computes nodes which is reliant on
rabbitmq_hosts settings

In current orchestration model - the only way to
fix configuration on nodes is to redeploy them.
Configuration will be applied from /etc/astute.yaml and
it is not enough to simply add additional PostDeployment
method in astute

Introduced additional setting for roles_metadata:
- update_required
  should store list of roles that dependends on this role

On deployment stage:
- make update_required list for the whole cluster
- select ready nodes without pending_roles and deploy them

No migration added to keep behaviour on old clusters as it is

DocImpact
Closes-Bug: 1368445

Change-Id: I1735a8b06531018b1240726f5faa4f7ce6e6a631
Merge "Redeploy cinder/compute nodes if new controller added"