NEW: added MAP for sct_extract_metric
NEW: added MAP for sct_extract_metric

Former-commit-id: 4e81d29a7ff2ad00a79a5281c630d1699ff15ddf
Former-commit-id: f96d415a78e9807970534d991ec5e40e214207c6
3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox,3324fr/spinalcordtoolbox