🌍 Low zoom locality names are missing translations + country, region zooms

[meetar]

tl;dr

The new Natural Earth v4.1 populated places file now includes localized names in a name_*, specifically:

1. Expands the name localization added in v4.0 to 21 languages (up from 7) and several
   dozen themes expanding from populated places to include all admin-0, admin-1,
   rivers, lakes, playas, geographic lines, physical labels, parks, airports, ports, and
   more. As part of this work a new unique and stable "ne_id" has been added for any
   feature with a name translation &/or a Wikidata ID concordance. The full list of
   languages is:

name_ar,
name_bn,
name_de,
name_en,
name_es,
name_fr,
name_el,
name_hi,
name_hu,
name_id,
name_it,
name_ja,
name_ko,
name_nl,
name_pl,
name_pt,
name_ru,
name_sv,
name_tr,
name_vi, and
name_zh

(Names with * indicate
new language in v4.1 series.) A 2-character language code decoder ring is here:
https://en.wikipedia.org/wiki/List_of_ISO_639-2_codes. Props to Wikidata for their
CC0 license: https://www.wikidata.org/wiki/Wikidata:Introduction.

This is for many themes, not just populated places. So work here should be generic for many theme imports.

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Original title: Include OpenStreetMap language data for Natural Earth features

For example, ocean names are available in many languages at zooms 9 and higher, but only in English at zoom 8 and lower. Example map: https://mapzen.com/tangram/play/?scene=https%3A%2F%2Fapi.github.com%2Fgists%2F9f177672cdaac4640ea1b519cde3420d#9.4233/13.3585/-38.4174

If you zoom out below zoom 9, the label disappears.

[nvkelso]

We'd need to match the selection of features shown in earlier zooms when changing the source, but the extra names would sure be nice.

[nvkelso]

Related: #1140

[nvkelso]

OpenMapTiles uses some nifty logic to merge city ranks between OpenStreetMap and Natural Earth, we could probably do similar for the names? (Keeping the Natural Earth features, but decorating them with additional OpenStreetMap names at runtime.)

• https://github.com/openmaptiles/openmaptiles/blob/master/layers/place/merge_city_rank.sql

[zerebubuth]

Might it make sense to do the inverse; keep the OpenStreetMap places, but decorate them with Natural Earth scalerank? We could do that regardless of zoom level, and have a consistent dataset for the whole zoom range.