Core/PacketIO: Requeue packets handled with STATUS_LOGGEDIN received before player is fully loaded in one step after packet processing loop - reduces used locks from 3 per packet to 1 per packet

(cherry picked from commit 8086a39210)

src/common/Threading/LockedQueue.h

@@ -57,6 +57,14 @@ public:
         unlock();
     }
 
+    //! Adds items back to front of the queue
+    template<class Iterator>
+    void readd(Iterator begin, Iterator end)
+    {
+        std::lock_guard<std::mutex> lock(_lock);
+        _queue.insert(_queue.begin(), begin, end);
+    }
+
     //! Gets the next result in the queue, if any.
     bool next(T& result)
     {