Implement aerialway labels (#1309)

This PR adds labels to `aerialway` linestrings after zoom level 12. I roughly followed PR https://github.com/openmaptiles/openmaptiles/pull/1179

These are useful in ski resorts and should not inflate the size of the tiles by much as aerialways are rare:
![Screenshot from 2021-11-18 12-18-58](https://user-images.githubusercontent.com/632493/142680225-1875904b-d146-4932-8a22-8c36919b875d.png)


Co-authored-by: Tomas Pohanka <TomPohys@gmail.com>

layers/transportation_name/transportation_name.sql

@@ -110,7 +110,7 @@ FROM (
            AND NOT highway_is_link(highway)
            AND
                CASE WHEN highway_class(highway, NULL::text, NULL::text) NOT IN ('path', 'minor') THEN TRUE
-                    WHEN highway IN ('unclassified', 'residential', 'shipway') THEN TRUE
+                    WHEN highway IN ('aerialway', 'unclassified', 'residential', 'shipway') THEN TRUE
                     WHEN route_rank = 1 THEN TRUE END
 
          UNION ALL

layers/transportation_name/update_transportation_name.sql

@@ -5,6 +5,7 @@
 
 -- etldoc: osm_transportation_name_network ->  osm_transportation_name_linestring
 -- etldoc: osm_shipway_linestring ->  osm_transportation_name_linestring
+-- etldoc: osm_aerialway_linestring ->  osm_transportation_name_linestring
 CREATE TABLE IF NOT EXISTS osm_transportation_name_linestring AS
 SELECT (ST_Dump(geometry)).geom AS geometry,
        tags,
@@ -65,6 +66,30 @@ FROM (
          FROM osm_shipway_linestring
          WHERE name <> ''
          GROUP BY name, name_en, name_de, tags, subclass, "level", layer
+         UNION ALL
+
+         SELECT ST_LineMerge(ST_Collect(geometry)) AS geometry,
+                transportation_name_tags(NULL::geometry, tags, name, name_en, name_de) AS tags,
+                NULL AS ref,
+                'aerialway' AS highway,
+                aerialway AS subclass,
+                NULL AS brunnel,
+                NULL AS sac_scale,
+                NULL::int AS level,
+                layer,
+                NULL AS indoor,
+                NULL AS network_type,
+                NULL AS route_1,
+                NULL AS route_2,
+                NULL AS route_3,
+                NULL AS route_4,
+                NULL AS route_5,
+                NULL AS route_6,
+                min(z_order) AS z_order,
+                NULL::int AS route_rank
+         FROM osm_aerialway_linestring
+         WHERE name <> ''
+         GROUP BY name, name_en, name_de, tags, subclass, "level", layer
      ) AS highway_union
 ;
 CREATE INDEX IF NOT EXISTS osm_transportation_name_linestring_name_ref_idx ON osm_transportation_name_linestring (coalesce(tags->'name', ''), coalesce(ref, ''));