Add a choropleth map renderer

Problem/Motivation

Choropleth map are very useful in many ways. Current dev has an example module that provides a choropleth map of the world. However, it would be more convenient to specify the map to use and how areas are named through parameters. Maybe an area description could be displayed if available on mouse over.

Sources

Use the example module as a basis to create a new renderer and add support for new parameters.
Other examples:
https://observablehq.com/@d3/choropleth/2
https://observablehq.com/@d3/world-choropleth/2

Data template

Proposed data template:

root:
  0:
    type: area
types:
  area:
    fields:
      id:
        type: string
        cardinality: 1
      description:
        type: string
        cardinality: 1
      value:
        type: number
        cardinality: 1