Simplify basemap

[mizmay]

It's entirely possible you prefer the original experience, it's just going to be harder to take further.

This PR just:

• removes unused imports
• turns off the forced isometric perspective animation
• creates a true light and dark mode (note it is possible to get much more granular with stylesheets on maps, and that's potentially a good idea, out of the box this dark style is very dark)

I moved the stylesheets to a local directory (this was necessary for the light editing required for these to work). You may need to disable CORS to test locally.

The stylesheets are open source, still using https://tiles.openfreemap.org/ for tile (reference layer) data.

Before	After	Dark