Removed NioTSO client and server

- NioTSO client isn't needed because we're using RayLib
- Added FreeSO's API server to handle most backend operations

server/FSO.Server.Database/DA/ISqlContext.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Data.Common;
+
+namespace FSO.Server.Database.DA
+{
+    public interface ISqlContext : IDisposable
+    {
+        DbConnection Connection { get; }
+        void Flush();
+    }
+}