[leddzgtw] Canonicalizable email addresses

Generate email addresses with error correcting code information embedded in them, probably something like your.name.123456@domain.tld, where 123456 is for error correction.

The goal is to make it easier for a sender to decode a difficult to read handwritten email address.

It will be a bit more difficult for address owner to memorize, because he or she won't be able to completely pick the username portion.

Have domain.tld implement some API to provide the correct address given an address with a few errors.  Integrate the query into mail user agents (MUA).