Currently when importing files, the parent left and right are recomputed on each record creation/update, which could lead to a lot a request.
This commit will defer the parent field recomputation to the end on the `load` function by recomputing the values from the MPTT and inserting directly the new values on the records.
Tested on a customer instance, this will reduce the execution time when importing a thousand stock.location from 15 minutes to several seconds.
Yannick Tivisse
fd089ee467