People: Add 675$a and adjust data

[jenniferward]

In Personal Names, RISM practice has been to use 670 to record forms of names found and reference sources consulted without finding anything. If the latter, a 0 is entered in $b. In MARC, the usual field for the latter is 675: https://www.loc.gov/marc/authority/ad675.html 675 is present in Works.

The RISM practice results in records where the 670 is mixing purposes, crowded, and hard to interpret, such as https://muscat.rism.info/admin/people/30018692 and https://muscat.rism.info/admin/people/139

We would like to:

• Add 675$a, non-repeatable, free-text field
• For any records with a 670 field with only 0 in $b, the $a should be moved to 675 and the 670 deleted.

For example, 30018692 would be: =675##$aEitnerQ, Grove|5, MGG suppl., RISM A/I suppl., RISM A/I, RiemannL|1|2/p suppl., RiemannL|1|2/p

and 670 would keep the references to DEUMM/b, Grove|6, and MGG.