Allow US choropleth maps to use strings

[mmr-crexi]

Feature Description
Choropleth maps right now require numbers per state. If there were strings, I could append a '%' to indicate percentage, or have a whole string (percentage, numerator, denominator) per state

Goal of Feature
Provide more utility for the choropleth map, and more detail for my users.

Current Solution
I have explanatory text below and allow them to look at query results

Alternative Ideas
Haven't really thought of any

Examples/Screenshots
Not without giving away proprietary info...

Are you interested in contributing this feature?
If I only had the time

[mcrascal]

Thanks @mmr-crexi.

Here's how we're thinking of this, lmk if any issues:

1. We need a numeric value to power the colouring in the choropleth.
2. We can make sure those values respect formatting tags, similar to the rest of the charts. (e.g. value_pct will render as a properly formatted percentage)
3. We can look at including an additional arbitrary string in the tooltip label, so that you could drop in additional info if you wanted to.

[mmr-crexi]

Ah got it-- so it seems that the field is serving double duty, one for scaling of color values and the other for direct display. I like the idea of string formatting, that will likely make a lot of sense-- having the ability to say what the numerator and denominator are for each state is where I want to be, because a 10% in Wyoming by population will be a very different number than a 10% in California.