Add pages showing the org teams

I think want at least the coala maintainers, coala developers and coala newcomer teams to have a page, with a list of team members similar to https://coala.io/#/getinvolved .

I think it is OK to have a page about all teams in https://github.com/orgs/coala/teams .

However we also need a way to name our temporary teams so that they do not appear on the website.

e.g. @adtac created a team to help him manage inactive newcomers at https://github.com/coala/meta/issues/74 , so they could be removed. Maybe we dont want a team like that appearing on the website ;-)