Remove plugins.gradle and factor into common extension

game/plugin/util/command/src/command.kt

@@ -0,0 +1,20 @@
+import org.apollo.game.model.entity.Player
+
+/**
+ * Checks whether the amount of arguments provided is correct, sending the player the specified
+ * message if not.
+ */
+fun valid_arg_length(args: Array<String>, length: IntRange, player: Player, message: String): Boolean {
+    val valid = length.contains(args.size)
+    if (!valid) {
+        player.sendMessage(message)
+    }
+    return valid
+}
+
+/**
+ * Checks whether the amount of arguments provided is correct, sending the player the specified
+ * message if not.
+ */
+fun valid_arg_length(args: Array<String>, length: Int, player: Player, message: String)
+        = valid_arg_length(args, IntRange(length, length), player, message)