XAFORUM-76: Integrate ForumCode.FlagsHome functionality inside Administration

This is an interesting approach and I like it (adding another button on the Homepage that take the Admins to the FlagsHome). 

We can either do it this way or integrate in the Administration. 

If we do it this way than maybe we should create a new issue called "Add an entry point for the Flag functionality", since in this Pull Request we are actually not integrating nothing in the Administration. Also we maybe could have used a new translation key called 'Moderate' instead of 'Flag List'.

The issue was supposed to create a new entry in the Administration's vertical-menu (by using ConfigurableClass). An example of Application that provides this kind of integration with the Administration is Recruitment, see http://design.xwiki.org/xwiki/bin/download/Proposal/RecruitmentImprovements/administration.png