[IMP] stock: remove _parent_store=True from model stock.quant.package

The model does not actually need this feature, as the hierarchies of packages
are not expected to be deep.  Performance wise, updating columns `parent_left`
and `parent_right` may actually suffer from concurrent updates that require
retrying requests.

addons/stock/models/stock_quant.py

@@ -559,10 +559,7 @@ class QuantPackage(models.Model):
     """ Packages containing quants and/or other packages """
     _name = "stock.quant.package"
     _description = "Physical Packages"
-    _parent_name = "parent_id"
-    _parent_store = True
-    _parent_order = 'name'
-    _order = 'parent_left'
+    _order = 'name'
 
     name = fields.Char(
         'Package Reference', copy=False, index=True,
@@ -575,8 +572,6 @@ class QuantPackage(models.Model):
     ancestor_ids = fields.One2many('stock.quant.package', string='Ancestors', compute='_compute_ancestor_ids')
     children_quant_ids = fields.One2many('stock.quant', string='All Bulk Content', compute='_compute_children_quant_ids')
     children_ids = fields.One2many('stock.quant.package', 'parent_id', 'Contained Packages', readonly=True)
-    parent_left = fields.Integer('Left Parent', index=True)
-    parent_right = fields.Integer('Right Parent', index=True)
     packaging_id = fields.Many2one(
         'product.packaging', 'Package Type', index=True,
         help="This field should be completed only if everything inside the package share the same product, otherwise it doesn't really makes sense.")