Extract formfields into discrete nexus-formfields-api module
Rename nexus-formfields-api module -> nexus-formfields
Merge pull request #501 from sonatype/extract-formfields-api

REVIEW: Extract formfields into discrete nexus-formfields-api module
Use non-depreacated components. Tidy up after plugin-manger refactoring.
[NEXUS-6560] Increase priority for zip mime types to avoid problem with html detection which as same priority
Merge branch 'master' into extract-mimetypes-api