Fix support for namespaced projects in the doc server
    
    We have added support for namespaced projects in pagure and we need to
    support hosting documentation for them but we have been using the
    following route:
    @APP.route('/<repo>/<path:filename>')</path:filename></repo>
    This means that we are unable to distinguish between:
    /repo/folder/file
    and
    /namespace/repo/file
    
    This commit fixes that making the URLs be namespace.repo before listing
    the folder and files.
    
    This commit also adjusts the unit-tests accordingly.