Comment 6 for bug 1744996

Here's a working branch:

http://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/berick/lp1744996-record-merge-tracking

1. Adds the columns and applies the values on record merge.
2. 2nd commit adds a message to the browser client bib record display indicating when a record was merged with another and links to the target record.

TODO: release notes.

To test:

[1] Add 2 or more records to a record bucket.
[2] Merge said records
[3] Confirm the merge warning appears in the subordinate records.
[4] Confirm the merge_date is also applied to the target record in the DB.