Conditional Shipping and Payments

1. Add the ability to restrict shipping methods based on percentage or number of bookings already booked on a date. Ie. When a date is 90% booked, show/hide X shipping method.

2. Add the ability to restrict shipping methods based on a booking date during a certain period of time. I.e. when a rental product is booked between X date/time and X date/time, show/hide shipping method.

These are extremely important for physical rental products that are shipped!