layer-shell: set_exclusive_zones with 2 parameters

When the anchor bitfield is set at a corner, such ar top|left, bottom|right and there is an exclusive_zone set, it will have no effect, as is not possible to infer what really the desized edge is: top or left.

add a new call set_exclusive_zones, intended to replace set_exclusive_zone which takes 2 parameters one intended for the op and bottom edges, vertical_zone and one intended for the left and right edges, horizontal_zone.