Extracting zip file to destened folder.

#5218 
The current work on 5218 deal with a subtheme imported from a github repository and cloned the theme to a folder with the name of the site and allow to two different vsites use the same subtheme without overriding each other.

This PR handle with subtheme imported from zip that need to copy to a folder with the name of the vsite.

There is a problem with copy the zip files: the files of the first level copied fine but folders are not copied.

This branch is a WIP - don't merge yet.