[overlord-issues] [JBoss JIRA] (ARTIF-706) Create DerivedExtendedArtifactType

Create DerivedExtendedArtifactType ---------------------------------- Key: ARTIF-706 URL: https://issues.jboss.org/browse/ARTIF-706 Project: Artificer Issue Type: Sub-task Reporter: Brett Meyer Having "relatedDocument" in an artifact's relationships list requires some stupid logic to deal with (see ArtifactVerifier#verifyNames). Instead, we should rely solely on the real #relatedDocument field. Unfortunately, that's only on DerivedArtifactType. If a derived artifact is an *extended* artifact, there's no access to that field, hence the need to use the general relationship. Re-work that structure to be more useful.