Feature Request: Marimekko

## Marimekko charts
Marimekko charts are able to consolidate two 100% stacked bar charts into one. Consolidating two related metrics helps in presenting the information concisely to viewers and results in eye-catching visuals.

## Rationale
Although LetsPlot certainly has the tools to create them, the number of data transformations needed might make Marimekko Bars a good addition to the Bistro Plots module.

## Expected inputs
Marimekko charts take four inputs:
- Labels to use for the X axis.
- An X axis metric which needs to be accumulated up to the plot size / Alternatively the number of entries of the label is counted.
- Labels to use for the Y axis.
- An Y axis metric which needs to be accumulated up to the plot size / Alternatively the number of entries of the label is counted.

## Examples

### Asset manager regions vs Asset managers per region

### Exported product distribution vs Main exporters per product

### Renewable energy jobs vs region distribution for each energy type

[Chart source](https://www.mekkographics.com/product/power-of-mekko-charts/)