Separate no-name POIs into a new layer

[nvkelso]

Like #2025, this issue tracks features in the POIs layer that are generally not business establishments and are more like street furniture but includes a wide range of structures and some natural features (like peaks and water springs). The earth layer also has a few label positions for islands and ridges that could move into this new layer? Or two layers structures (most of these moving from pois layer) and a natural (stuff that would have been labels in earth or water layers if they weren't already in pois, or are in earth)?

WARNING: This is a breaking SemVer change.

These generally fall into the no_name_okay section of the POIs layer:

• https://github.com/tilezen/vector-datasource/blob/master/yaml/pois.yaml#L380-L475

Maybe if it's a PONI then at the end it moves into a new layer with a transform? Or we just move those kinds outright to a new layer – and duplicate some of the source_layer: pois logic in https://github.com/tilezen/vector-datasource/blob/master/queries.yaml?

There might be a few kinds from that list that should remain in pois layer, though, like man_made = observatory, or duplicated between? Some others: quarry, dog_park, pitch, field_hospital, health_centre, alpine_hut, information, picnic_site, viewpoint, wilderness_hut, dam, car_rental, car_wash, customs, fuel, money_transfer, ranger_station, border_control, harbour_master, playground, boatyard.