Make certbot role install httpd

This role tries to put file in /etc/httpd/conf.d, httpd should be
installed first.

roles/certbot/tasks/main.yml

@@ -1,6 +1,7 @@
 - name: Install the needed packages
   package: name={{item}} state=present
   with_items:
+  - httpd
   - certbot
 
 - name: Create directory for ACME challenge