[EAP_CD] [EAP7] Make the "jboss-eap-cd.zip" a plain artifact

The "jboss-eap-cd.zip" artifact was previously cached in CE cacher service. Since the CE Cacher was decommissioned, the image build utilizing the "eap-cd-15" module now fails with the error message cekit / concreate not being able to retrieve it (without explicitly adding it to the cache manually).

The current implementation should be changed to use plain artifacts instead.

Note: While this JIRA was created just for the case of eap-cd-15 module, the underlying issues should be corrected in all branches / releases, where applicable.