[MERGE] *: create records in batch

Ensure main Odoo models supports batch record creation.

* `purchase.order.line` supports multi creation in `purchase`, but not anymore when `purchase_stock` is installed.
* `sale.order.line` supports multi creation in `sale`, but not anymore when `sale_purchase` is installed.
* `crm.lead` doesn't support batch creation atm, but it doesn't cost anything to support it.

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closes odoo/odoo#50468

Signed-off-by: Victor Feyens (vfe) <vfe@odoo.com>