R1:4b248e354587

Make the "Add Auditors" Herald rules use modern transactions

Summary:
Ref T10978. Convert "Add Auditors" rules in Herald to modern modular transactions.

Here and in D17262 (and in the next change), I've removed "audit reasons". There are several reasons for this:

- They're pretty hacky.
- They store English-language (well, usually) text in the database, which can't be translated.
- I think they may not be necessary. When they were written, Herald did not apply transactions, so it was less clear…