Refactor to use module acm-certificate to create the cert

[ddriddle]

To avoid code duplication it would be best to use module acm-certificate as a submodule to create the certificate. One challenge to consider is that this module performs a data lookup on the zone. The same lookup is performed in the acm-certificate module. To avoid unnecessary lookups we need the ability to pass the zone_id instead of the domain name to the submodule (See acm-certificate#10).