Ladybird: Implement basic cookie support

We import the CookieJar class from Browser to do the work. Long-term
we should look for a way to share this code with Browser.

Ladybird/CMakeLists.txt

@@ -34,6 +34,7 @@ find_package(Qt6 REQUIRED COMPONENTS Core Widgets Network)
 
 set(SOURCES
     BrowserWindow.cpp
+    CookieJar.cpp
     RequestManagerQt.cpp
     main.cpp
     WebView.cpp