get_here_nodes_within should offer _option_ of limiting to congestion network nodes

[Nate-Wessel]

Currently this is the default and it makes certain conflations impossible, like
/node/centreline/13459492?doConflation

because the query is limited to nodes of the congestion network. In that case the nearest node is 381m away!

[Nate-Wessel]

This gives the right results but is still taking unacceptably long (~2s)

SELECT 
    here_nodes.node_id::int,
    ST_AsGeoJSON(here_nodes.geom, 5) AS geom,
    array_agg(DISTINCT InitCap(streets.st_name)) FILTER (WHERE streets.st_name IS NOT NULL) AS street_names
FROM here.routing_nodes_23_4 AS here_nodes --USING (node_id)
JOIN here_gis.streets_att_23_4 AS streets USING (link_id)
GROUP BY
    here_nodes.node_id,
    here_nodes.geom
ORDER BY ST_Transform(here_nodes.geom, 2952) <-> ST_Transform(
        ST_SetSRID(ST_MakePoint(-79.355866287, 43.691944099), 4326),
        2952
    )
LIMIT 10;

even after

CREATE INDEX ON here_gis.zlevels_23_4 USING gist ( ST_Transform(geom,2952) )

Seems it's still doing a sequential scan...