[16.0][ADD] mrp_subcontracting_purchase_stock_price_unit_sync

[AungKoKoLin1997]

This module extends 'purchase_stock_price_unit' functionality to also work with subcontracting purchase orders.
Depends on: OCA/purchase-workflow#2137

@qrtl

[rinaldifirdaus]

Hi @AungKoKoLin1997, i just did a quick test with subcontracting scenario for FIFO product.
Result:

1. Unit price of the finished product on SVL updated upon changing the unit price on PO.
2. Somehow, its only updates with the finished product unit price from the PO itself. where the unit price on inventory valuation of Finished goods should be adjusted with formula: "Finished Product = Resupplied component + Component from the vendor + Cost of the finished product"

Could you please take a look on this?

[github-actions]

There hasn't been any activity on this pull request in the past 4 months, so it has been marked as stale and it will be closed automatically if no further activity occurs in the next 30 days.
If you want this PR to never become stale, please ask a PSC member to apply the "no stale" label.

[AungKoKoLin1997]

We have planned not to use this feature for our project and we don't have time to work on for this feature. So, everyone who needs this feature can supersede this PR with the improvements.