SES: `Identity` with `value` *and* `hostedZone`

### Describe the feature

As far as I can see, currently you can create an `Identity` with
- an arbitrary domain without the `hostedZone` for automatic setup, or
- a `hostedZone` which is then automatically used as the domain/`value`.
It would be nice if you could provide specify both, a domain/identity a subdomain of the hosted zone..

### Use Case

Production has hosted zone `company.com` and has the CDK app deploy into that directly.
PR preview stages have hosted zone `company.dev`, but have the app deploy into `.company.dev`.

### Proposed Solution

_No response_

### Other Information

_No response_

### Acknowledgements

- [ ] I may be able to implement this feature request
- [ ] This feature might incur a breaking change

### CDK version used

2.194.0

### Environment details (OS name and version, etc.)

linux

Start with the CDK SES Identity construct and trace how its current value and hostedZone inputs determine the identity domain. Define the behavior for an explicitly supplied subdomain alongside a hosted zone, then add coverage showing that the requested identity and hosted-zone setup are both preserved.

Written by the indexing model from the issue text.