Update Code Logic and Documentation around ACM Certificates

[gargana]

The Documentation isn't as clear as it should be around DNS requirements for Hosted Zones and ACM Certificate Domain ownership verfication.

• The Zone must be publicly resolvable.
• DomainName and HostedZone must be used together
• If only the ACM Certificate is provided we should indicate to the user that they should create and alias to the Name of the ELB created by the stack.

Code:

• We should update the code to use the new ACM Certificate submodule to push the maintenance of that logic updstream and simplify this QuickStart