Merge branch 'document-ephemeral-storage-configuration' into 'master'

Document addition of ephemeral_storage configuration to Operational Container Scanning

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/167522



Merged-by: Russell Dickenson <rdickenson@gitlab.com>
Approved-by: Shao Ming Tan <smtan@gitlab.com>
Approved-by: Russell Dickenson <rdickenson@gitlab.com>
Co-authored-by: Yasha Rise <yrise@gitlab.com>