Provide a public Disaster Recovery policy/process statement

Problem

Customers keep contacting us with questionnaires and questions about our DR processes, RTO/RPO commitments, sometimes going into detail, sometimes for compliance but also for their own internal audits. While our playbooks are public, answering the questions is still time consuming.

Solution

Compile a one-page public (controlled) document stating our practices (perhaps enhancing or building on the existing https://handbook.gitlab.com/handbook/engineering/gitlab-com/policies/backup/) that is added to trust.gitlab.com.

Execution

Let's use this issue to compile a list of questions being asked, and use them to drive a document that describes our practices.

cc @mjwood @rnienaber @jarv