ENYO-2935: full async & zero-copy `ares-generator.js` (much faster)

* The list of file to be handled is now an `Array` of
  `{ name: xxx, path: yyy}` where `name:` is the expected output file
  name and `path:` is the location where the file is.
* When possible (move, rename, copy) changes are done on `name`,
  leaving the bits un-touched.
* File content edition is done on the bits referred to by `path:` using
  copy-on-write & operating directly on a temporary copy.

Enyo-DCO-1.1-Signed-off-by: Francois-Xavier KOWALSKI <francois-xavier.kowalski@hp.com>