[REM] stock: remove unused fields of stock.move

3 fields were useless in `stock.move` (only one store):
- `picking_partner_id` not used and we should use `partner_id` instead
- `backorder_id` not used and no sense
- `note` (store), not used and always empty. remove it.

task-2424248

addons/stock/models/stock_move.py

@@ -94,8 +94,6 @@ class StockMove(models.Model):
         copy=False,
         help="Optional: previous stock move when chaining them")
     picking_id = fields.Many2one('stock.picking', 'Transfer', index=True, states={'done': [('readonly', True)]}, check_company=True)
-    picking_partner_id = fields.Many2one('res.partner', 'Transfer Destination Address', related='picking_id.partner_id', readonly=False)
-    note = fields.Text('Notes')
     state = fields.Selection([
         ('draft', 'New'), ('cancel', 'Cancelled'),
         ('waiting', 'Waiting Another Move'),
@@ -112,7 +110,6 @@ class StockMove(models.Model):
     price_unit = fields.Float(
         'Unit Price', help="Technical field used to record the product cost set by the user during a picking confirmation (when costing "
                            "method used is 'average price' or 'real'). Value given in company currency and in product uom.", copy=False)  # as it's a technical field, we intentionally don't provide the digits attribute
-    backorder_id = fields.Many2one('stock.picking', 'Back Order of', related='picking_id.backorder_id', readonly=False)
     origin = fields.Char("Source Document")
     procure_method = fields.Selection([
         ('make_to_stock', 'Default: Take From Stock'),