Turn config into a class to permit Hiera overwritting

[tux-o-matic]

@rodjek's original module exposed logorate configuration via the base class and this fork made config a defined resource.
PR #6 allowed to pass a hash to the init class to create a config resource.
But that doesn't change the fact that unless you're using Hiera deep merge (not the default Hiera conf), you won't be able to overwrite specific configuration parameters in your different Hiera levels.

[fbarbeira]

+1