Add Developer Outreach specialties to the Team page

I was confused by the following comment about the Developer Relations Team (DevRel):

• https://gitlab.com/gitlab-org/gitlab-ce/issues/27272#note_22102602

There doesn't seem to be any reference to this team on the Team Page or the handbook.

Can we add the relevant specialties to members on the team page?

@seanpackham @marcia