A helper function that returns a list of paths for files provided
in 'args'. Each argument must be a cons cell where car is
either :stylesheet or :script and cdr is a name of the file.

Useful when generating a list of dependencies for widgets and/or the
application (see 'widget-public-dependencies' and
*application-public-dependencies*.)

Ex:
(get-public-files-paths '(:stylesheet . “navigation”)
'(:script . “effects”))
=> (#P“stylesheets/navigation.css” #P“scripts/effects.js”)