More first time contributor exposure

Description

gitlab-ce!13902 added a badge to MRs which indicate first-time contributors to a project. The following improvements would be nice to have:

  • the information available for searching in MR pages;
  • visible in the list of MRs; and
  • available through the API.

Proposal

Add the badge information to more places.

Links / references

gitlab-ce!13902

Documentation blurb

Overview

Why should someone use this feature?

API availability would make it easier to have "welcome!" messages from robots. Having it visible on the MR listing would make it easier to see it and not have it lost in a sea of other MRs.

Use cases

Who is this for? Provide one or more use cases.

Promoting the existing first time contributor feature to have more visibility/access.

Feature checklist

Make sure these are completed before closing the issue, with a link to the relevant commit.

/cc @mbergeron