Extend the Config Tool object model to support Shinken-specific *modulation objects

This extends the Thruk Config Tool's object model to support the (poorly documented) Shinken-specific businessimpactmodulation, resultmodulation, and checkmodulation objects. Of these I actually have need to use businessimpactmodulation; the other two were done for the sake of completeness.

Since there doesn't appear to be proper documentation of these objects on Shinken's site, the help text is a mix of stuff I adapted from other objects in the same file, and comments from sample configs (e.g. in shinken_specific.cfg).  I thought it better to have something than nothing.  In the same way, the attribute names and types come directly from Shinken's source code for the modules concerned, rather than from documentation.