Ecoregions tiles, offer on portal

[kgeographer]

The ecoregions data is large, and not worth making a dataset just to get it in the tileset-making pipeline, so...

• [x] create a tileset for it directly on tileboss, and
• [x] make the layer available on the Place Portal page

Data here: https://drive.google.com/drive/folders/1A8EZAS7ACD_NluwhfzPoM5sPq0HRZa_k?usp=drive_link

• a shapefile zip; more attributes than we need;
• eco_name is an identifier back to wiki landing pages, e.g. https://en.wikipedia.org/wiki/Northern_Mesoamerican_Pacific_Coast_Mangroves

[docuracy]

• [x] Group types:
  • [x] Realm (8)
  • [x] Biome (16 = forests, grasslands, or deserts)
  • [x] Ecoregion (867)
• [x] Regenerate multilayer ecoregions.mbtiles:
  • [x] Polygons
  • [x] Labels (largest for realms, explode for others)
• [x] Add ecoregion source and layers to whg-basic styles' json:
  • [x] variable fill-color based on color property
  • [x] Use whg:switchgroup and whg:switchlabel metadata properties to ensure addition to style switcher