Verified_fields: Allow librarians to lock certain work/edition fields

[mekarpeles]

Describe the problem that you'd like solved

As of:

• #7495 ...when we encounter new data (such as new publishers) the importer biases towards appending them to the list. In some cases where a librarian has verified a publisher (or book cover) we may want to lock these fields to prevent confusion: as described in:
• #7744

For now, let's start with publishers and covers as fields librarians can lock

• the UI might introduce a checkbox (librarian-only) on the /edit page next to covers and publishers to lock these fields
• the importer should ignore importing fields which existing the verified_fields array
• the verified_fields should exist on both the work and the edition

Stakeholders

@seabelis

[mheiman]

This is potentially useful on its own, but I'm not entirely sure that this directly addresses the issue that @seabelis is seeing.

The appending of extraneous data isn't in any way limited to editions that librarians have touched; probably the vast majority of cases are on records that no one's even noticed yet. As I understand it, what's happening is:

1. The importer creates an edition and populates the record (hopefully correctly)
2. A later import matches that same edition and merges in new, less useful data

As I see it, it looks like a pure import problem. There are any number of ways we could address it, such as:

1. Configure the importer to just stop appending new data to populated fields (globally or specific fields)
2. Establish some ranking of data sources, and use that to resolve differences (e.g. if an edition was created from an IA MARC record, then a BWB import can't modify any already populated fields)

In the abstract, I think a librarian lock for fields we don't want messed with is probably a good and useful thing, but I don't think it really resolves the problem that prompted the idea.