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/Updates/DbUpdateAddon.cs

@@ -0,0 +1,14 @@
+using System;
+
+namespace FSO.Server.Database.DA.Updates
+{
+    public class DbUpdateAddon
+    {
+        public int addon_id { get; set; }
+        public string name { get; set; }
+        public string description { get; set; }
+        public string addon_zip_url { get; set; }
+        public string server_zip_url { get; set; }
+        public DateTime date { get; set; }
+    }
+}