Summary:
Previously, ref/reflist columns were formatted entirely based on their visible column, since they received values from the visible or display columns rather than the actual row IDs. This creates `ReferenceFormatter` and `ReferenceListFormatter` which still delegate most of the formatting work to a visible column formatter but fix a few issues:
- ReferenceList columns now actually use the options (e.g. date format) of the visible column to format their elements. Previously they were formatted generically because the visible column formatter wasn't expecting a list.
- Invalid references aren't formatted with an `#Invalid Ref` prefix.
- When the ref column displays the Row ID, it doesn't have a visible or display column. Previously this led to the references being formatted as just numbers in most cases, with special code in the widget to display them like `Table1[2]`. Now they are consistently formatted in that style throughout.
Test Plan: Updated existing tests.
Reviewers: jarek
Reviewed By: jarek
Subscribers: dsagal
Differential Revision: https://phab.getgrist.com/D3212
8f531ef622