Enable gitlab pages

Fixes #228 (closed) and supersedes !163 (closed). Enables easy resolving of #61 (closed).

The test page is online at https://test.archlinux.org/. Its project is here: https://gitlab.archlinux.org/svenstaro/pages-test/pages It uses the GitLab built-in Let's Encrypt integration.

Changes are already rolled out.

Upon inspection and merging, the reviewer must:

• Remove hetznerdns_record.gitlab_pages_test_* from archlinux.tf and run terraform apply
• Remove the project https://gitlab.archlinux.org/svenstaro/pages-test

docs/gitlab-pages.md

@@ -3,7 +3,7 @@
 In order use GitLab Pages with Arch Linux, you'll have to specifically request a custom subdomain
 below `pkgbuild.com` or `archlinux.org` to be assigned. We don't allow random projects to use Pages
 because of legal and safety reasons (we don't want people to be able to trick others into thinking
-something hosted below one of our domains is offiical).
+something hosted below one of our domains is official).
 
 ## Setup on GitLab's side