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/DatabaseScripts/changes/0001_3_max_avatars.sql

@@ -0,0 +1,6 @@
+CREATE TRIGGER `fso_avatars_BEFORE_INSERT` BEFORE INSERT ON `fso_avatars` FOR EACH ROW BEGIN
+ IF (SELECT COUNT(*) FROM fso_avatars a WHERE NEW.user_id = a.user_id) >= 3 THEN
+  SIGNAL SQLSTATE '45000'
+  SET MESSAGE_TEXT = 'Cannot own more than 3 avatars.';
+ END IF;
+END