Implement mediawiki.cookie module

Provides functonality similar to WebRequest#getCookie and WebResponse#setcookie.

Wraps $.cookie and automatically takes care of wgCookiePrefix etc.

Bug: 49156
Change-Id: I217ef258aecf1acd335e2cea56ae08b22541c7d4
Co-Author: Matthew Flaschen <mflaschen@wikimedia.org>
Co-Author: Timo Tijhof <krinklemail@gmail.com>
Merge "Implement mediawiki.cookie module"