Add Italian phone number validation method

Summary:
Added a new validation method phoneIT. This method allows the validation of Italian phone numbers according to the standard format used in Italy.

Details:

• Added the phoneIT method to validate Italian phone numbers.
• The method checks whether the input follows the format of Italian phone numbers, including the country code (+39).

Usage:

$( "#myForm" ).validate({
  rules: {
    phone: {
      required: true,
      phoneIT: true
    }
  }
});