Split up the internal details of the org.sonatype.nexus.email package.
Remove use of internal configuration model in validator api.
Drop legacy UI support.
apply header
properly pass username from config
Merge branch 'master' into split-email-internal
Merge pull request #583 from sonatype/split-email-internal

REVIEW: Split up the internal details of the org.sonatype.nexus.email package.