Allow data mapper when showing the Data Table

**Is your feature request related to a problem? Please describe.**
We are using a custom field to show transparent or colored regions in a layer(kepler colorField). That field is also used to store whether a region is selected or not. When showing the data table we wouldn't like the user to see numbers, but to map those values to some strings.

**Describe the solution you'd like**
A possible mapper for every field so when showing data table it could use the mapper to show custom values for the user

**Describe alternatives you've considered**
Have't come up with an alternative

**Additional context**
This is what it looks like

I'd like that field to show: