[IMP] base,doc: add on_create and edit attribute on gantt view
[IMP] base,doc: add on_create and edit attribute on gantt view

related task #1929079

closes odoo/odoo#33872

Signed-off-by: Jérome Maes (jem) <6964489703ed973b467c16e75b2abe91a57e12f6@openerp.com>
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo