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/Assistants/AssistantHandler.cs

@@ -76,7 +76,7 @@ public static class AssistantHandler
         _handshakes[m] = Timer.DelayCall(TimeSpan.FromSeconds(30), OnTimeout, m);
     }
 
-    public static void AssistVersion(NetState state, CircularBufferReader reader, int packetLength)
+    public static void AssistVersion(NetState state, SpanReader reader, int packetLength)
     {
         // We are not supporting the old UOAssist protocol
         // var assistVersion = reader.ReadInt32();
@@ -87,7 +87,7 @@ public static class AssistantHandler
         state.Assistant = assistVersion.ContainsOrdinal(' ') ? assistVersion : $"RazorCE {assistVersion}";
     }
 
-    private static void HandshakeResponse(NetState state, CircularBufferReader reader, int packetLength)
+    private static void HandshakeResponse(NetState state, SpanReader reader, int packetLength)
     {
         Mobile m = state.Mobile;