[webui] don't link to the revisions in the commit feed

As we have the revision in the payload, we can link directly to the diff
[api] always set package_kind without delay

setting the package kind is pretty fast and shouldn't interfer with delayed
jobs parsing issues (SLOW)
[api] don't generate events for review->new state changes

Every submitter gets 2 emails and this is considered spam. RequestChange
is emitted anyway