Release 2.1.0 - Improve DNS failover using intermediate CNAME records

[forevermatt]

Added

• Add intermediate CNAMEs for easier failover
• Output domain names used by DNS CNAME failover records

Fixed

• Wait for certificate to be issued before trying to use it

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Note: If desired, you could use terraform state mv to reduce the amount of deletion-and-recreation that some included terraform module-renames and resource-renames will cause (if that matters to you):

terraform state mv module.dns_for_failover.module.fail_over_cname module.dns_for_failover.module.fail_over_cnames
terraform state mv module.dns_for_failover.module.custom_domains module.dns_for_failover.module.api_gateway_domains_and_certs