Likely we want the group smtp email job to retry. Also added a check to
see if we already have an email log entry for the message to avoid
possible duplicates on retry.
Related previous commit: 5e70b74cb8
This change ensures we use the base62 sha1 for videos when quoting
because this is what the composer is used to using. With a valid base62
sha1 the composer already knows how to fetch the placeholder image for
it.
Fallbacks have been created to continue to support the old way as well
as a fix for the old way so that the thumbnail continues to display when
quoting. These fallbacks are in place so that we don't have to rebake
all posts that contain videos. If we ever do that we may remove these
fallbacks.
