Create documentation for setting up and using the out-of-tree provider #686
Description
With the in-tree provider becoming obsolete, we need basic documentation that covers the following:
- Key concepts about the out-of-tree provider (what is it, why/when would you use it, components and architecture)
- Basic set up and configuration of the out-of-tree provider (what core components use the --cloud-provider config, IAM requirements, GCP VPC requirements)
- Migration from the in-tree provider (high-level migration overview with best practices to minimize unexpected disruptions)
Collaborators: @aojea @BenTheElder
/assign