Server block LWRP and nxensite/nxdissite script

Created a LWRP for creating, deleting, enabling and disabling nginx server blocks. And added site enable / disable script written by @perusio
the "root" attribute is the web root folder, not the site configuration directory. Maybe `root` isn't a good name for it and should be changed to `webroot` or something else more self-explanatory?
And maybe an setting attribute would be nice after all `default["nginx"]["webroot"]` or something like that, @phlipper ?