AWS::SES::DomainIdentity

# Scope of request

Be able to create and verify SES domain identities (similar to how ACM certificates can be created and verified) including DKIM. Rough outline of the process:
1. CloudFormation creates the resource.
2. CloudFormation spits out the DNS records that need to be created for verification (TXT for domain and CNAMEs for DKIM).
3. Something in AWS checks and verifies the records.
4. The domain is added and ready to use.

# Expected behavior

See previous section. That's just a high-level idea, it doesn't have to be exactly that process but something along those lines probably makes sense.

# Suggest specific test cases

Pass in the domain you want to add/verify as a string and CloudFormation spits out the DNS records for verification in the console (or elsewhere).

# Links to existing API docs
[SES APIs](https://docs.aws.amazon.com/ses/latest/APIReference/Welcome.html)
[VerifyDomainDkim](https://docs.aws.amazon.com/ses/latest/APIReference/API_VerifyDomainDkim.html)
[VerifyDomainIdentity](https://docs.aws.amazon.com/ses/latest/APIReference/API_VerifyDomainIdentity.html)
[ListIdentities](https://docs.aws.amazon.com/ses/latest/APIReference/API_ListIdentities.html)

# Category tag

Other (SES)