Config validation rewrite part 1

src/main/java/com/gmail/nossr50/util/upgrade/UpgradeManager.java

@@ -19,6 +19,12 @@ public class UpgradeManager extends BukkitConfig {
         loadKeys();
     }
 
+    @Override
+    protected void validateConfigKeys() {
+        //TODO: Rewrite legacy validation code
+        // Look into what needs to change for this
+    }
+
     /**
      * Check if the given {@link UpgradeType} is necessary.
      *