2FA: Migrate the TWO_FACTOR hash algorithm

[ljacqu]

Unfortunately we cannot perform our usual way of migrations with the TWO_FACTOR hash algorithm since it means a TOTP key is stored in the database.

I'd suggest to migrate the current TWO_FACTOR password (on success) to the new totpKey column and to set some random password (ew, I know) to the user. Unless we can force the user to set a new password right after a successful TWO_FACTOR code was input.

Ensure that TWO_FACTOR can no longer be set as hash config in the config.yml file.