Evaluate GitLab + Gitter

There was a lot of discussion about which chat platform to recommend for Drupal communities and Gitter was not really considered.
But since Drupal git is moving to GitLab and GitLab owns Gitter, there might be a benefit of using their chat client.
Or have a clear list of requirements, what do we expect from a chat client used by the Drupal community, and check if it is or could be implemented in Gitter.

#2490332: Evaluate whether to replace drupal IRC channels with another communication medium
#2954073: Promote Rocket Chat instance as an alternative to Slack

Source: https://www.drupal.org/project/issues/rss/infrastructure