feat: add DeleteById function

[Adam0Brien]

Fix: #97
feat: users now have the option to delete a specific rule.

Rule numbers can be found by using the following command:
sudo iptables -t nat -L PREROUTING -n --line-number

Example usage:

        table := "nat"
	chain := "PREROUTING"
	ruleIDToDelete := 2

	// Use the DeleteById function to delete the rule.
	result, err := iptables.DeleteById(table, chain, ruleIDToDelete)
	if err != nil {
		fmt.Printf("Error: %v\n", err)
	} else {
		fmt.Println(result)
	}