docs: Add AWS account details and debugging guidance for macOS runners

Expands the macOS runner documentation with some infrastructure details and debugging information. Adds Google Cloud project information (gitlab-ci-155816) and AWS account IDs for medium (215928322474) and large (730335264460) Mac runners in another place in the docs. Includes some debugging guidance highlighting the unique characteristics of macOS dedicated hosts, including their bare metal nature, extended provisioning times, and hardware availability constraints.

Issue: MacOS on AWS debugging playbook / logs / dashbo... (gitlab-org/ci-cd/shared-runners/infrastructure#296 - closed) • Davis Bickford