[RFC][VOTE] Password Digest Mechanism Registry

There's been no further discussion about password digest registry after the initial post on 15 Oct despite a reminder post a week later, so I'm going to go ahead and move the RFC into voting. https://wiki.php.net/rfc/password_registry Reminder that this RFC is mostly non user facing, it just provides mechanisms for extensions to register hashing handlers for the password_*() functions. The primary user-facing effect of this is that password scheme identifiers have changed. There is a secondary question on the RFC to address the BC impact of this. -Sara