Allow the setting of mode, group and owner on share directory.

Samba requires that the share directory has proper unix permissions before users can modify it. This pull request adds the functionality to set the owner, group and mode within the shares data bag.
Oh man I forgot this pull request existed! 

I think I did it this way in order to allow the end user the ability to set the owner, group and mode on each individual share. If you put that information at the same level as the individual exports, it would be global across them all right?

I totally understand not wanting to break backwards compatibility.