erp5_trade: allow editing reference date method on Trade Model Path
Supersedes !2123 (closed)
This MR allows editing a previously hidden property from a Trade Model Path.
Here is a screenshot from a Trade Model Path view before the change. "Term Reference Date" allows selecting movement from which Trade Phase will be used to select the reference date for generated movements matching the TMP. The reference date is then be used to compute Start and Stop Dates of the generated movement.
However, every movement can define its own methods for getting a reference date, especially, one may want to use either Start Date or Stop Dat. For instance, for a Packing List, start date (Shipping Date) may be defined on the basis of an Order start date (Shipping Date also).
A generic property exists for deciding which method defines the reference date:
reference_date_method_id. It will always default to getStopDate, and this MR simply shows a
field to edit the method on a TMP view.