Make better use of search metadata for filtering searches

[caro401]

The search provider for the docs pagefind allows you to annotate bits of a page with specific metadata, to help filter down to relevant results when you're searching. Currently the filters available in the search are only applied to the auto-generated plugin docs, and the filter values are a relic of a past experiment.

You can see the currently available filters in the search box - type anything, and notice at the top of the results there's some sections module, author, tags etc, which contain checkboxes. Checking any of the checkboxes reduces your search results to just pages with metadata that matches the boxed you checked.

We should have a think about how users generally want to filter down search results in the docs. One idea was to filter by different page/content types (#32 which can be done entirely in this repo), but I think other things like references to specific operations/modules, or plugins (at a specific version) might also be helpful? This will require updates in the DHARPA-Project/kiara-svelte-components repo to implement.

Any feedback from docs users about how you'd like to be able to filter your searching would be really helpful!