sentry.gitlab.com should authenticate against ops.gitlab.net, gitlab.com, or Google apps, not dev.gitlab.org

Currently sentry.gitlab.com uses oauth against dev.gitlab.org for authenticating GitLab users.

This should be moved over to either use Google apps, like much of our infrastructure now does, or possibly ops.gitlab.net.

We want all developers within the company to be able to access Sentry as this help make them aware of, and own, their production issues.

As far as I know, not all developers still have dev.gitlab.org logins.