MBS-5757: reduce open time for all edits to 7 days

http://tickets.musicbrainz.org/browse/MBS-5757

We decided in the meeting to change everything for now, and pull back or amend to only non-destructive edits if we decide this is a problem.

I don't mind this, but if we merge this now it means that edits entered on beta get the 7-day expiration and edits entered on production get 14-day expiration. If we want to avoid this, we'll have to merge it right at the next release instead.