Use gon.gitlab_url instead of location.hostname
Created by: felixfbecker
This is the last blocker for https://gitlab.com/gitlab-org/gitlab/merge_requests/16556.
gon.gitlab_url
is the canonical URL that that Sourcegraph would be accessing Gitlab under, not location.hostname
.
Refactored globals.d.ts a bit to declare all the globals as actual globals instead of only on Window
(they are still on Window
with this change).