[Bar chart] Configure the max width of the bars

**Is your feature request related to a problem? Please describe.**
We would like to configure the maximum width of the bar(s) for bar charts that do not have a time axis.

For example

or

**Describe the solution you'd like**
Maybe it would make sense a setting in pixels but I am open to any suggestions.

**Kibana Cross Issues**
[Add any [Kibana](https://github.com/elastic/kibana) related issues/feature requests here.](https://github.com/elastic/kibana/issues/147847)