[ADD] web: adds file upload mixin

This commit adds mixin to manage file uploads in view controllers and to
display progress bars.

The first motivation and use case is to allow MRP to manage and display
uploads like in Documents.

closes odoo/odoo#38397

Task: #2074822
Related: odoo/enterprise#5887
Signed-off-by: Alexandre Kühn (aku) <aku@odoo.com>