fixes #117

change prod stream search layout

change prod user assignment forms to filter groups

fix re-promoting deactivated prod officer

add custom short-name proceedings field

change available statuses on stream

move status change element to summary

change layout of fields
add status filtering
add date / status ordering

Authors will now be able to attach files to
their feedback form for the proofs sent by the production
team. The attachment is linked to the ProductionEvent that
is created with the feedback.