Document AWS bare metal in the Red Hat Ranch default routing

Bare metal requests on the Red Hat Ranch no longer need to name one of the aws-07-bare-metal to aws-10-bare-metal pools. Artemis sends requests with virtualization.is-virtualized to AWS bare metal first, and falls back to Beaker.

• Jira: TFT-5202
• Depends on: https://gitlab.cee.redhat.com/baseos-qe/ansible-baseos-ci/-/merge_requests/12863. Merge this MR after that one reaches production.

Changes

• Drop the pool list and the --pool examples from the "Bare Metal Instances in AWS" section.
• Add a note asking users to stop naming the deprecated pools.

Generated-by: Claude Code