feat: better author edit via Rfc update API

[jennifer-richards]

This adds a proper update algorithm to #10048 and can either replace that PR or be updated / merged afterwards.

Instead of doing a bulk drop and replace when a new set of authors comes in, uses an algorithm based on the existing update_documentauthors() method to adjust existing author records and create reasonably human readable logs. Treats author records with the same Person as equivalent and, if there is no Person, uses equal titlepage_name. This will result in some silly logs related to organization authors but these are rare. This could be improved a bit without extraordinary effort, but the returns seem marginal to me.

This deals somewhat transparently with an upgrade from DocumentAuthor to RfcAuthors for an RFC. It does not add an explicit flag that the underlying models have changed, it just notes changes in the data, though in almost every case the name is changed. For this purpose, documentauthor.person.plain_name() is used as the stand-in for titlepage_name when deciding how to describe the change. This matches up with what we've been presenting at red and with the display on the datatracker document page.

Also, the event messages translate the internal titlepage_name to "name" in the change descriptions. That is, if "Jennifer Richards" is changed to "J. Richards", the log will look like "changed name from 'Jennifer Richards' to 'J. Richards'".

Also: this doesn't populate RfcAuthor.email at all. It doesn't remove it from the model either, it just leaves it alone for now.