UI: Add per-profile browser panel cookie management

Allows the ability to switch cookies between profiles.  Allows the
ability to, for example, switch streaming service accounts between
profiles for proper access to the pages displayed by the browser panels
(such as chat windows).

UI/window-basic-main.cpp

@@ -79,7 +79,12 @@ using namespace std;
 #endif
 
 struct QCef;
-QCef *cef = nullptr;
+struct QCefCookieManager;
+
+QCef              *cef           = nullptr;
+QCefCookieManager *panel_cookies = nullptr;
+
+void DestroyPanelCookieManager();
 
 namespace {
 
@@ -1097,6 +1102,8 @@ static const double scaled_vals[] =
 	0.0
 };
 
+extern void CheckExistingCookieId();
+
 bool OBSBasic::InitBasicConfigDefaults()
 {
 	QList<QScreen*> screens = QGuiApplication::screens();
@@ -1302,6 +1309,8 @@ bool OBSBasic::InitBasicConfigDefaults()
 			VOLUME_METER_DECAY_FAST);
 	config_set_default_uint  (basicConfig, "Audio", "PeakMeterType", 0);
 
+	CheckExistingCookieId();
+
 	return true;
 }
 
@@ -2247,6 +2256,7 @@ OBSBasic::~OBSBasic()
 #endif
 
 #ifdef BROWSER_AVAILABLE
+	DestroyPanelCookieManager();
 	delete cef;
 	cef = nullptr;
 #endif