[IMP] Inventory: Bringing least packages current

[fw-bot]

While working on the removal strategies overview script, I realized that the documentation for "Least packages removal" was out of date. In this PR, I did the following:

• Added a section about enabling the removal strategy
• Added a subsection about storing products in packages before they can be used
• Added subsections on enabling the strategy on the location or product category
• Updated screenshots to be current
• Updated language to be current with 18.3 forward

All of this work makes the last of the removal strategies docs consistent with the other removal strategies docs.

This saas-18.3 PR can be FWP up to master.

Forward-Port-Of: #15753

[robodoo]

[fw-bot]

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

• [IMP] Inventory: Bringing least packages current #15808
• [IMP] Inventory: Bringing least packages current #15806

To merge the full chain, use

@robodoo r+

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

[erjer-odoo]

@robodoo r+