[add] information re:naming conventions for the DA Strapi collections

[ll-zerr]

Create a section that explains the approach taken to naming the Strapi collections.

• Higher level/ umbrella concept (like Geo or Product) versus
• Lower level/ specific aspect of that umbrella (Region, Subregion of Geo and Category, Item of Product)
• Include examples
• (optional) include an image with the examples
• add a link to this section in the table of contents for the collections.md