Bug 12958: Set a fund owner to a fund hierarchy

Bug 12958: Set a fund owner to a fund hierarchy

This patch adds the ability to set an owner to a fund hierarchy
On editing a fund, if it has children, a new checkbox appears "Set this
owner to all children funds".
If checked, all the fund hierarchy will herit to this owner.
This will facilitate the fund owner modifications.

Test plan:
- Verify that the new checkbox only appears if the fund has at least a child.
- Create a consistent fund hierarchy, something like:
    fund1
      fund11
        fund111
      fund12
    fund2
      fund21
- Try to modify a fund owner without checking the checkbox. Verify the
  children have not been modified.
- Try to modify a fund owner with checking the checkbox. Verify all fund
  hierarchy has been modified.

Signed-off-by: Frederic Demians <f.demians@tamil.fr>
It works as announced.

Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Tomas Cohen Arazi <tomascohen@gmail.com>