S109 - Magic Numbers: add an "authorized numbers" parameter

Original thread for the ML: http://sonarqube.15.x6.nabble.com/squid-S109-Magic-Numbers-ignore-2-td5035346.html

The rule S109 deprecates rules MagicNumber from CheckStyle and AvoidLiteralsInIfCondition from PMD. However, the current implementation is too sensitive regarding Checkstyle's version and not enough strict regarding PMD's version.

Authorized values by implementation:

• Java plugin S109: -1, 0, 1
• CheckStyle MagicNumber: -1, 0, 1, 2
• PMD AvoidLiteralsInIfCondition: -1, 0

In order to stay coherent, a parameter allowing to manage authorized values should be added to the rule, with default value being -1,0,1