HOLI-9555 location based recos tests

See merge request app/holi-app-volunteering!42

HOLI-9524: use index and fix distance calculation

See merge request app/holi-app-volunteering!41

* query now (implicitly) uses the HNSW index on embedding_array
* query now uses the `<#>` operator to sort by distance which can (and will) take advantage of the
  index for the newly introduced `location_gps` column which combines (`longitude`,`latitude`) into
  a PostGIS geometry
* distance calculation is fixed - it calculated before with two different units (distance in
  "angle" (RSID 4326) vs. distance in meters (RSID 3857, Pseudo-Mercator plane projection))

HOLI-9542 resolve lat lng using geolocationId

See merge request app/holi-app-volunteering!40

HOLI-9483 add location as a weighted ranking criterion to recommendations

See merge request app/holi-app-volunteering!37

Rationale: I've had several instances in which test code would not compile. Compilation only would
suffice but as tests run very quickly I think it doesn't harm to also check for them to be green. If
this turns out to be impractical we can just compile instead.

HOLI-9534 use geolocationId instead of PlaceDetails

See merge request app/holi-app-volunteering!38

Upcoming MRs will then make use of the geolocationId by querying the needed details from the GeoAPI
service.

This should only be used in local development.

HOLI-9147 don't require db env configuration in fake mode

See merge request app/holi-app-volunteering!36

HOLI-9147: add recommendations endpoint

See merge request app/holi-app-volunteering!35