Allows users to submit suggestions for updates/additions to specific fields on existing video records

[avanavana]

Two possible methods of execution

1. New "Updates" table, analogous to "Submissions", where records are duplicates of existing records, with different field content.
2. Leverage existing "Submissions" table, distinguish as "update" behavior by simply using whether a "Submission" record already has a Zotero Key+Version or not, and/or corresponding "Video" record in the DB.

• In the submissions table, indicate visually which are new submissions and which are updates, and which fields are being updated, with colors.