[FIX] stock: properly calculate stock at planned date

[wtaferner]

Description of the issue/feature this PR addresses:
Currently the decision is always taken based on free quantity which is available quantity - reserved qty and therefore does not take into consideration future deliveries or already ordered quantities incoming today or in the future.

Thus, when there is a planned date in procurement we calculate the scheduled date to determine at which point in time we would expect the fulfillment of the procurement and see if there is a need to procure based on MTO or not and act accordingly.

Current behavior before PR:
Unrelated if there is already an inbound order planned, mto is used if not enough quantity is available now

Desired behavior after PR is merged:
Taking into consideration the virtual quantity at the point in time where we want to fulfill the order determines whether or not MTO is triggered.

Info: @wt-io-it

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[robodoo]

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[amoyaux]

Hey @wtaferner it seems to be a big behavior change in stable. I'm a bit afraid to do this. Also the patch only check for the min schedule date which could be not true neither if procurements have different planned date.
However we are currently improving MTSO and we will handle this kind of usecases. You can find the PR here #147112

[wtaferner]

@amoyaux
No worries, thx for letting me know that it is improved/fixed at least for 18.0. Therefore I am closing this PR and just use it for my own purposes or others can take it if stumbling over it.
The change in 18.0 looks rather big, so hope you guys tackle all the important use cases and stuff in relation to that...not sure if I can help and review, but at least I will follow what is done in the end.

Have a great day! 😄