Feature/v4 certify

[steven-schattenberg-itential]

This change adds:

• A playbook to verify that the servers are suitable for installation.
• A playbook to certify an installation that has occurred.
  • An associated set of tasks to perform the certification, one per component
  • A template to aggregate the certification results

This change also replaces the old preflight role and removes those files.

[kvelarde-itential]

I think there are still some playbook/role structure issues. Let's discuss on a call.

[kvelarde-itential]

As part of the integration with the new redis role, I think we will want to split this file into a certify-redis.yml and certify-sentinel.yml since redis and sentinel may run on different hosts.

[steven-schattenberg-itential]

Agreed. I'd like to get this first iteration merged and then circle back and break out sentinel into its own certify and verify. I still have to merge the v4 redis changes anyway.