Search features in database

[tomalrussell]

User may want to search for individual features (OSM roads, WDPA polygons...) by name or ID

Note on search - currently calls out to Nominatim API to provide place search, no link to our data layers at all.

Feature ideas: PostgreSQL search functionality on name/ID fields - possible advanced search form allows focus on sector or dataset. pg_trgm gives basic fuzzy matching.