Add support for "PagerDuty External Status Pages"

[allyjweir]

Hi folks 👋

We are in the process of adopting PagerDuty's status page product. We would ideally like to manage the provisioning and configuration of these from Terraform however I notice that there is not currently a resource type available.

The 'business service' resource that helps make us the status page's configuration is already available.

Would it be possible for the Terraform provider to be extended and to introduce support for managing External Status Pages?