Use the sync-project-config role in service-zuul

We can sync the project-config repo instead of cloning it on the
hosts.

Change-Id: Ic238d743f4dda0a3c04a7e3618a9d86d3c3e5371

.zuul.yaml

@@ -1592,6 +1592,9 @@
           label: ubuntu-xenial
         - name: zuul01.openstack.org
           label: ubuntu-xenial
+    required-projects:
+      - openstack/project-config
+      - opendev/system-config
     vars:
       run_playbooks:
         - playbooks/service-letsencrypt.yaml

playbooks/roles/zuul/tasks/main.yaml

@@ -119,11 +119,9 @@
     group: zuul
     mode: 0600
 
-- name: Clone project-config repo
-  git:
-    repo: https://opendev.org/openstack/project-config
-    dest: /opt/project-config
-    force: yes
+- name: Sync project-config
+  include_role:
+    name: sync-project-config
 
 - name: Install docker-compose
   package: