create aws-control-tower-detective-enabler

Out of the [aws-securityhub-multiaccount-scripts](https://github.com/awslabs/aws-securityhub-multiaccount-scripts) the [aws-control-tower-securityhub-enabler](https://github.com/aws-samples/aws-control-tower-securityhub-enabler) was created.

And from [amazon-guardduty-multiaccount-scripts](https://github.com/aws-samples/amazon-guardduty-multiaccount-scripts) arose [aws-control-tower-guardduty-enabler](https://github.com/aws-samples/aws-control-tower-guardduty-enabler).

It would be great to have the same thing for AWS Detective, since I already used the two "enablers" above in our org and am very happy with the results. This would complete the suite of org-level security tools AWS offers.