[WKPlugins] Added leechcraft_wkplugins_qtplugin static plugin part.
[WKPlugins] Find and moc qwebkitplatformplugin.h.
[WKPlugins] Added basic NotificationsExt.
[WKPlugins] Basic QWebKitPlatformPlugin implementation.
[WKPlugins] Reuse created extensions object.
[WKPlugins] Import StaticPlugin.