[aws-certificatemanager] Add fromCertificateName method to Certificate object

There is currently a `fromCertificateArn` method on the `Certificate` object but the problem with using this is that the ARN could change if the resource is recreated leading to any stack referencing this ARN breaking. My proposal gives, I believe, a more robust way of referencing a certificate that would survive the recreation of this resource.

### Use Case

In order to reference pre-existing certificates by their name

### Proposed Solution

Create a `fromCertificateName` method on the `Certificate` object

* [ ] :wave: I may be able to implement this feature request
* [ ] :warning: This feature might incur a breaking change

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This is a :rocket: Feature Request

Start by locating the Certificate object and its existing fromCertificateArn entry point, then inspect the surrounding ACM implementation. Done means pre-existing certificates can be referenced by name, with coverage for the new fromCertificateName method.

Written by the indexing model from the issue text.