Indicate whether a job was manually triggered in the Jobs API

Problem to solve

In our automation we'd like to know whether job was triggered manually.

Target audience

Further details

Proposal

field manual with possible values true or false could be added here: https://docs.gitlab.com/ce/api/jobs.html#get-a-single-job, the same way it's visible here https://docs.gitlab.com/ce/user/project/integrations/webhooks.html#pipeline-events

What does success look like, and how can we measure that?

Links / references