Re-organize in-memory character profile storage.

Now uses a dictionary of int -> profile instead of an array filled with nulls.

Content.Shared/Network/NetMessages/MsgDeleteCharacter.cs

@@ -0,0 +1,33 @@
+using Lidgren.Network;
+using Robust.Shared.Interfaces.Network;
+using Robust.Shared.Network;
+
+namespace Content.Shared.Network.NetMessages
+{
+    /// <summary>
+    /// The client sends this to delete a character profile.
+    /// </summary>
+    public class MsgDeleteCharacter : NetMessage
+    {
+        #region REQUIRED
+
+        public const MsgGroups GROUP = MsgGroups.Command;
+        public const string NAME = nameof(MsgDeleteCharacter);
+
+        public MsgDeleteCharacter(INetChannel channel) : base(NAME, GROUP) { }
+
+        #endregion
+
+        public int Slot;
+
+        public override void ReadFromBuffer(NetIncomingMessage buffer)
+        {
+            Slot = buffer.ReadInt32();
+        }
+
+        public override void WriteToBuffer(NetOutgoingMessage buffer)
+        {
+            buffer.Write(Slot);
+        }
+    }
+}