AWS::GuardDuty - [Coverage] - Add export findings configuration

### Name of the resource

AWS::GuardDuty::Detector

### Resource name

AWS::GuardDuty::PublishingConfiguration

### Description

Currently it is not possible to configure the findings S3 bucket for an AWS GuardDuty detector. This means it is not possible to configure automatic exporting of findings to an S3 bucket.

Docs:
- https://docs.aws.amazon.com/guardduty/latest/ug/guardduty_exportfindings.html

Relevant API's:
- https://docs.aws.amazon.com/guardduty/latest/APIReference/API_CreatePublishingDestination.html
- https://docs.aws.amazon.com/guardduty/latest/APIReference/API_UpdatePublishingDestination.html
- https://docs.aws.amazon.com/guardduty/latest/APIReference/API_DeletePublishingDestination.html

Not sure if this should be part of the existing `AWS::GuardDuty::Dectector` resource, as its a separate API it might warrant a new `AWS::GuardDuty::PublishingConfiguration` resource.

### Other Details

_No response_

Start with the GuardDuty export findings documentation and the linked CreatePublishingDestination, UpdatePublishingDestination, and DeletePublishingDestination API references. Determine whether coverage belongs on AWS::GuardDuty::Detector or requires AWS::GuardDuty::PublishingConfiguration; done means the chosen resource can configure automatic findings export to an S3 bucket.

Written by the indexing model from the issue text.