Make some commands debug only, update Mesa biome

src/main/resources/lang/en_us.yml

@@ -5,6 +5,7 @@ enable:
 disable:
   - "Thank you for using Terra!"
 command:
+  debug-only: "This command must be used with debug mode enabled!"
   player-only: "This command is for players only!"
   terra-world: "This command must be executed in a Terra world!"
   invalid: "Invalid command. (Expected %1$s arguments, found %2$s)."