LP1891369 Renewal due date extensions

LP1891369 Renewal due date extensions

When an item is renewed before it's due date, libraries now have the option
to extend the renewal's due date to include any time lost from the early
renewal.

For example, a 14 day checkout renewed after 12 days will result in a due date
on the renewal of 14 days plus 2 days to cover the lost time.

New Org Unit Settings

* circ.renew.extend_due_date

Enables this new feature

* circ.renew.extend_due_date.min_duration_percent

Specifies how early in a checkout a renewal will result in an extended
due date.  E.g. A value of 50 (percent) means no due date extension
would occur if an attempt to renew occurred after 5 days of a 14 day
circulation duration.  In this case, the renewal would still be allowed,
it just wouldn't get the extended due date.

Signed-off-by: Bill Erickson <berickxx@gmail.com>