Localize labels into the user’s preferred language

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Since OpenTrailMap uses the same multilingual vector tiles as OSM Americana, it should also attempt to label features in the user’s preferred language. Unfortunately, OSM Americana’s label localization functionality isn’t reusable yet (osm-americana/openstreetmap-americana#914), but OpenTrailMap could temporarily use the more basic mapbox-gl-language plugin as a temporary workaround.