Summary:
- Update styling of label, id, and "derived ID from label" checkbox.
- Implement a label which shows 'Data Column' vs 'Formula Column' vs 'Empty Column',
and a dropdown with column actions (such as Clear/Convert)
- Implement new formula display in the side-panel, and open the standard
FormulaEditor when clicked.
- Remove old FieldConfigTab, of which now very little would be used.
- Fix up remaining code that relied on it (RefSelect)
Test Plan: Fixed old tests, added new browser cases, and a case for a new helper function.
Reviewers: paulfitz
Reviewed By: paulfitz
Differential Revision: https://phab.getgrist.com/D2757
