Add GitLab Pages to CE

We received a feature request to add GitLab Pages to CE:

https://twitter.com/framasky/status/712597323843551232

Luc ‏@framasky .@gitlab Would it be possible to have gitlab-pages in the community edition in the future? We, @framasoft, a non-profit organisization 1/2

https://twitter.com/framasky/status/712597515397423104

Luc @framasky @gitlab @framasoft are often asked to add it to our open-to-everyone Gitlab CE instance. 2/2