Add documentation for run command endpoint

[Gman98ish]

Pre-Request Checklist

• [x] Passes rubocop code analysis (try rubocop --auto-correct)
• [x] Tests added or adapted (try rake test)
• [x] Changes are reflected in the documentation
• [x] User-visible changes appended to CHANGELOG.md

Description

Adds documentation for new run command endpoints

See https://github.com/ytti/oxidized-web/pull/216

[mortzu]

Please fix the merge conflict