guess From address from Received headers

guess From address from Received headers

When replying to a message notmuch tries to pick the correct From
 address by looking which one of a user's configured email addresses
 were included in To or Cc headers of the email that is being replied to.
 If none of the users email addresses are in the To or Cc headers we now
 try to guess from the first (chronologically, last) Received header
 which domain this email was received in and therefore which of the
 email addresses to use in a reply
 If that fails we still use the primary email as From email

Signed-off-by: Dirk Hohndel <hohndel@infradead.org>