Custom Domain documentation Outdated

[jobannon]

When customers are using the new hosting platform, the custom domain steps are slightly different than outlined in Cloud doc (no cutover steps differ, etc)

See https://fusionauth.zendesk.com/agent/tickets/79418 for ad-hoc instructions given to customer

Referenced doc needing updating - https://fusionauth.io/docs/get-started/run-in-the-cloud/cloud#unlimited-custom-domains

[mooreds]

This has similar complexities to the way we handled the outbound IP addresses. While we move platforms, we should consider how to handle this.

All new customers are on the new platform. There is a significant, but decreasing number of customers on the old platform.