Hardcoded default colormap per variable

[Karinon]

The old default dataset hat pre-defined colors per variable. @wachsylon asked if we could hardcode default colors for certain variable names.

[d70-t]

I'd love to see a mapping from variabies to colors (or better generic metadata). We've talked (in various rounds) over and over again, that we'd need something like this for various projects. So Ideally, I'd imagine we'll have some file (e.g. JSON, YAML, CSV etc...) at a well know location, which would associate some generic information to a variable. I could imagine we'd like the CF standard_name as a key, but probably we'll additionally want some other identifiers (like common variable names etc...). As value, I'd see an extensible set of attributes, e.g.:

• default colormap
• typical value range (min / max) -> useful for having fixed colorbars
• typical resolution (might be data-source dependent though, either absolute or relative) -> useful for compression settings, especially together with range