Comment 6 for bug 1829295

Lightly cleaned patch from internal code:

https://git.evergreen-ils.org/?p=working/Evergreen.git;a=shortlog;h=refs/heads/user/berick/lp1829295-shelf-expire-honors-closed-and-hours

The main assumption that needs some consideration is that hold shelf expire intervals are assumed to be defined in days (not hours, weeks, etc.). We probably need a separate setting which explicitly defines the expire interval as a day count (e.g. circ.holds.default_shelf_expire_days). This simplified the code a good bit, and I'm guessing this is the most common use case.

In short, if an org unit has any open hours on a given day (starting 'tomorrow'), it counts as "1 day" of the expire interval.