[FW][IMP] Inventory: Rewrite aging report as stock valuation report

[fw-bot]

This doc has been rewritten to address the following:

• The Inventory Aging Report doc is no longer needed because this report was combined into the Stock Valuation Report (in the pivot view).
• The Stock Valuation Report, by default, is in list view. This doc overwrites the Inventory Aging Report to instead focus primarily on the Stock Valuation Report list view, including all the updated/new fields shown in this view.
• Parts of the former Inventory Aging Report are still covered in the Stock Aging Report section.
• A section was added to described the graph view of this report.
• A few other sections were added to describe important contextual information about stock valuation and how it is calculated (e.g. perpetual vs. periodic accounting, SVLs)

Odoo Project task # 4320416

Forward-Port-Of: #11720

[robodoo]

[fw-bot]

@benderliz this PR targets master and is the last of the forward-port chain containing:

• [FW][IMP] Inventory: Rewrite aging report as stock valuation report #11837

To merge the full chain, use

@robodoo r+

More info at https://github.com/odoo/odoo/wiki/Mergebot#forward-port

[fw-bot]

@benderliz this forward port of #11720 is awaiting action (not merged or closed).