feat: Adds a memory mirrored ring buffer for networking. (#1533)

## Breaking Changes

Incoming packet registration signature has changed to:
```cs
delegate* void OnReceiveCallback(NetState state, SpanReader reader, int packetLength);

IncomingPackets.Register(int packetID, int length, bool ingame, OnReceiveCallback onReceive);
```

For example, an incoming packet handler signature would now look like this:
```cs
public static void SomeIncomingPacket(NetState state, SpanReader reader, int packetLength)
{
    // Parse the data
}
```

## Summary

Updates the network Pipe class to use a mirrored memory technique. This technique involves mapping the same physical memory to two contiguous virtual memory spaces so the byte buffer appears duplicated. This allows writing to a double-sized array to wrap around without the need for the `CircularBuffer` classes.

In practice this allows us to use `Span<byte>` as if the buffer was a regular array.


### Bug Fixes

- [X] Fixes bad fixed length string parsing

Projects/Server/Network/PacketHandler.cs

@@ -13,13 +13,15 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  *************************************************************************/
 
+using System.Buffers;
+
 namespace Server.Network;
 
 public unsafe class PacketHandler
 {
     private readonly int _length;
 
-    public PacketHandler(int packetID, int length, bool ingame, delegate*<NetState, CircularBufferReader, int, void> onReceive)
+    public PacketHandler(int packetID, int length, bool ingame, delegate*<NetState, SpanReader, int, void> onReceive)
     {
         _length = length;
         PacketID = packetID;
@@ -31,7 +33,7 @@ public unsafe class PacketHandler
 
     public virtual int GetLength(NetState ns) => _length;
 
-    public delegate*<NetState, CircularBufferReader, int, void> OnReceive { get; }
+    public delegate*<NetState, SpanReader, int, void> OnReceive { get; }
 
     public delegate*<int, NetState, out bool, bool> ThrottleCallback { get; set; }