AWS::Route53Resolver::ResolverEndpoint - Add ipAddresses as a return attribute

[guidola]

1. AWS::Route53::ResolverEndpoint - Add ipAddresses as a return attribute

2. Scope of request

AWS::Route53::ResolverEndpoint should have an additional return attribute that can be later fetched through the !GetAtt function which allows to retrieve the ip addresses of the created ENIs.

This would allow to dynamically tie other resources that may use those values as part of their configuration such as a AWS::EC2:VpnClientEndpoint

3. Expected behavior

Calling !GetAtt inboundEnpoint.ipAddresses would return an array containing the ip addresses available for resolution.

6. Category (required)

4. Networking & Content (VPC, Route53, API GW,...)

[2018ik]

Duplicate of #172