Using a cert named after the primary domain with `_legacy` appended.
However, the cert is only issued for the legacy domains, not the primary
domain.

Deploy for `ipxe.archlinux.org`.

Fixes: archlinux/releng#22

Fixes: 26f289b7 ("Capitalize the first letter of all task names")

Added some documentation regarding the service_nginx_template variable and the implications of
using it.

docs/maintenance.txt: Add the documentation for the maintenance mode with example on how to plug it into another role.