For now that's mostly a no-op.

Once we use this role user to postpone issues & MRs, this will:

 - avoid release managers getting subscribed to notifications
   of every postponed issue;

 - avoid the need for release managers' personal GitLab account
   to have access to every confidential issue in every project;

 - remove one blocker for migrating such GitLab automation
   to our infrastructure, so that RMs don't need the ability
   to impersonate the role-release-automation user anymore.