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/UOContent/Network/Packets/IncomingVendorPackets.cs

@@ -13,6 +13,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>. *
  *************************************************************************/
 
+using System.Buffers;
 using System.Collections.Generic;
 
 namespace Server.Network;
@@ -25,7 +26,7 @@ public static class IncomingVendorPackets
         IncomingPackets.Register(0x9F, 0, true, &VendorSellReply);
     }
 
-    public static void VendorBuyReply(NetState state, CircularBufferReader reader, int packetLength)
+    public static void VendorBuyReply(NetState state, SpanReader reader, int packetLength)
     {
         var vendor = World.FindMobile((Serial)reader.ReadUInt32());
 
@@ -65,7 +66,7 @@ public static class IncomingVendorPackets
         state.SendEndVendorBuy(vendor.Serial);
     }
 
-    public static void VendorSellReply(NetState state, CircularBufferReader reader, int packetLength)
+    public static void VendorSellReply(NetState state, SpanReader reader, int packetLength)
     {
         var serial = (Serial)reader.ReadUInt32();
         var vendor = World.FindMobile(serial);