Updates Gitlab runner documentation
This branch modifies the documentation around Gitlab runners. With the new prefixed publisher runners, we're now able to make runners namespaced to each team that wants to use this feature.
GitLab (git.doit.wisc.edu) will be patched at 10PM on Tuesday, 12/3, requiring a brief outage. In addition, the Container Registry will be unavailable 10PM-12AM on 12/3 while maintenance is performed.
This branch modifies the documentation around Gitlab runners. With the new prefixed publisher runners, we're now able to make runners namespaced to each team that wants to use this feature.