ENYO-1020: Move top-level Ares MVC components under ares/source/

- the `model/` tree was not attached to one of the functional Ares
  components (Ares, Harmonia, Phobos, Deimos)

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