collections detail view: allow filtering for specific location

[fhennig]

Currently for each variant in the details view, we show the count. But it'd be great if we could restrict it to a certain location, using the location filter.

Problem: At the moment we do not know the name of the location fields for each organism. For date, we have the 'mainDateField' in the config, but not for location fields.

Should we add this this to the dashboard config as well? Seems like the obvious way to go, only drawback is that the config is growing in size again. If we were to add this, I'd propose to call the new setting locationFields and it's a list, probably in most cases [region, country].

Edit: Turns out that in the staging application config, we already have a bunch more settings configured, but only for victoria:

    victoria:
      lapis:
        url: "https://api.loculus.staging.genspectrum.org/b-victoria"
        mainDateField: "sampleCollectionDateRangeLower"
        locationFields:
          - "country"
          - "division"
        authorAffiliationsField: "authorAffiliations"
        authorsField: "authors"
        ...

Interesting! This was added in 1d80909 — feat(website): add influenza B and B/Victoria dashboards (#615)

Edit2: Turns out that for denv there are also already location fields defined.

[fhennig]

ok, so actually, we have the locations in the organism constants already, I found. But it's hardcoded in the code,not in the config. But that would be fine.

But I now also vibe-coded a PR to move all that into the config: #1123 - but maybe we don't actually want that.