webpositive: Fix for HaikuWebKit 1.8.1

Change-Id: I00b2b01bf84e0d22ec759511b2f9435403207c95
Reviewed-on: https://review.haiku-os.org/c/haiku/+/4150
Reviewed-by: Alex von Gluck IV <kallisti5@unixzen.com>

WebPositive: add a cookie manager.

* Allows you to view and delete cookies.
* The list of domains is hierarchized and collapsed to minimize the
number of empty entries
* All cookie parameters are shown for each domain: name, path, value,
expiration date, and known flags.