Track usage of entities on client pages in a database table (on the client wiki). Usages that should/could be tracked:

• the item linked on wikidata (already tracked on the repo side)
• other items referenced explicitly on the wiki page
• items used indirectly, e.g. because their label is shown on a page
• properties used to access statements of items on a page

There should be an abstraction layer that allows code to access the list of entities used by a given page, and conversely, the list of pages using a given entity on a given wiki.