Add functions to handle GitHub workflows/runs in the Platform shared library

This is needed by NXP-31603 to run the "Docker image scan" GitHub Actions workflow from the nuxeo-lts Jenkins pipeline.

Let's implement at least the following commands with the flags we want to use, see https://cli.github.com/manual/:

gh workflow run [<workflow-id> | <workflow-name>] [flags]
gh run list [flags]
gh run view [<run-id>] [flags]
gh run watch <run-id> [flags]