[idea][feature-request] Vega/Vega-Lite Chart Support

[hydrosquall]

Description

There are chart types that aren't exposed yet, such as a waterfall or diverging bar . While some of these do have echart equivalents , deciding what props to expose can be effortful.

Instead of implementing these one at a time, I would like to use Vega/Vega-Lite definition directly from the Vega gallery.

What problem would this solve?

This would allow me to have the exact charts I'm looking for from inside evidence, instead of switching to a different tool / using a screenshot.

I saw Vega was previously evaluated. While it may not be used for the most frequently used charts, perhaps it can still play a supporting role! #136 (comment)

How should it work?

Then I would reference the variable in my chart component:

{% vega_lite_chart
	data="result_of_my_sql_query"
	spec={{
           mark: 'bar',
           encoding: {
              "x": { field: 'year' },
              "y": { field: "sales" }
           }
        }}
/%}

[hydrosquall]

Proof of concept branch: #3252