vector layer support (stamen maps)

[maphouse]

As mentioned in element, Stamen will turn its baselayers from traditional raster tile layers into vector layers. The service will also be migrated to Stadia maps. Use will apparently remain free but will require a stadia api key, and is effective as of fall 2023 (i think). This could have implications for nunaliit since many instances rely on the popular watercolour, toner and toner-lite layers. Useful links:

• https://stamen.com/here-comes-the-future-of-stamen-maps/
• https://docs.stadiamaps.com/guides/migrating-from-stamen-map-tiles/

[alexgao1]

For Atlascine: https://github.com/GCRC/nunaliit/commit/610c430f412e1da9f0b62867bd18a4a8ec4155ca