[17.0][ADD] product_margin_report_sale_margin

[edescalona]

@BinhexTeam

This new module allows you to add two new fields for the sales margin in the Product Margins report.

[christian-ramos-tecnativa]

LGTM! I’d like to add more context to these two new fields. Currently, this report includes all sales and purchases in the range by default when calculating the values.
For example, if I’ve purchased 100 tables but only 10 have been sold so far, the margin will appear negative, which can be misleading. In this case, the report seems to reflect more of a cost vs. revenue view of the product rather than actual profitability.
Here’s a screenshot to illustrate the scenario:

This new values add a lot of value to this report.
Thanks

[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.
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[rrebollo]

Code Review: Great work! The code looks good to me (LGTM). Thank you for your contribution! I've provided a few suggestions for your consideration—feel free to address them as you see fit.

[adasatorres]

Code review, LGTM!

[edescalona]

ping @legalsylvain