returns a formatted list of the contents of a folder on the server
syntax {up folder_list=path | template=##file## (##size)}
##file## : path/filename.extension
##fullpath## : path (without slash)
##relpath## : relative path (without slash)
##basename## : name and extension
##filename## : name without extension (without dot)
##extension## : extension
##size## : file size
##date## : Last modification date