Two attempts of dealing with sorting (and resequencing) in tabbed (multi-pages)
x2many editable lists (see odoo/odoo@c2563db and odoo/odoo@983c7ae) have been
previously done, using a static attribute (`keepChangesUnsorted`) on the
datapoint.
This solution sadly only covers both cases separately, not if they are combined.
Morever, onchanges were not correctly managed in neither of these two cases.
A new approach is used here, by "freezing" and "unfreezing" the datapoint when
needed, which is more flexible.
Some modifications have been introduced:
- when ordering a x2many, all records are now considered (and not only the
records on the current page) ; an additional read is thus done on the sorted
field for all records in the x2many relation
- `setSort` is now asynchronous as a `read` might be needed
Christophe Matthieu
b7ee1aa4b1