Add report for possible duplicate release groups (MBS-3586)
Add DuplicateReleaseGroups to the reports index page
Merge remote branch 'origin/beta' into reports-duplicate-rgs

Conflicts:
	root/report/index.tt
	root/report/release_group_list.tt
Lowercase release group titles before applying regexes
Check that days, months, and years are non_empty in Data::Link::find

Seeding empty strings for these fields via the /relationship-editor
endpoint will trigger an ISE.
Also delete empty date fields in WS::js::Edit; add a test
Merge remote-tracking branch 'nikki-bitbucket/reports-duplicate-rgs' into beta

* nikki-bitbucket/reports-duplicate-rgs:
  Lowercase release group titles before applying regexes
  Add DuplicateReleaseGroups to the reports index page
  Add report for possible duplicate release groups (MBS-3586)
Merge remote-tracking branch 'bitmap/non-empty-date-values' into beta

* bitmap/non-empty-date-values:
  Also delete empty date fields in WS::js::Edit; add a test
  Check that days, months, and years are non_empty in Data::Link::find