[NX-232] Staging upload
[NX-232] Validate form on load
Merge branch 'master' into NX-232-staging-upload-ui
Merge branch 'master' into NX-232-staging-upload-ui
Merge pull request #584 from sonatype/NX-232-staging-upload-ui

REVIEW: [NX-232] Staging (bundle) upload UI