Horizontal Bar Chart should allow better axis configuration

[jentfoo]

The horizontal bar chart swaps the value and category axis's. This results in the axis configuration not being fully functional for this chart type. Notably a user may also want to configure the min and max values or other range configurations, which are currently not possible on the x-axis.

We wont want to add these fields to the xaxis struct since they wont generally be useful, instead we need an API change in v0.6.0 so that the horizontal bar chart axis structs are more specific to the chart type (similar to what we did in the heat map chart type).

Ideas:

• Deprecate the horizontal version of the bar chart struct and instead just have a Horizontal bool in BarChartOption. This would require us to change from Y/X axis configuration into ValueAxis and CategoryAxis, with new structs matching those needs. This expands our Axis API, but could provide a natural option for bar charts which is closer aligned to the violin chart.