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

roles/prometheus/files/node.rules.yml

@@ -201,18 +201,6 @@ groups:
       summary: "Prometheus TSDB WAL truncations failed (instance {{ $labels.instance }})"
       description: "Prometheus encountered {{ $value }} TSDB WAL truncation failures\n  VALUE = {{ $value }}\n  LABELS: {{ $labels }}"
 
-- name: arch
-  interval: 60s
-  rules:
-  - alert: pacman_security_updates_pending
-    expr: pacman_security_updates_pending > 0
-    for: 1m
-    labels:
-      severity: warning
-    annotations:
-      description: 'host {{ $labels.instance }} has a vulernable but update-able package'
-      summary: '{{ $labels.instance }} has {{ $value }} vulnerable packages'
-
   - alert: pacman_updates_pending
     expr: pacman_updates_pending > 50
     for: 1m