Document process for chart-level setting customization

[jwildfire]

Document how to customize chart settings. Specifically, customizations related to chart appearance are not currently well supported (per questions from @waterhob)

Early Notes:

• This isn't currently well supported or documented
• Standard config process surfaced on the mapping page is designed for column mappings shared across multiple renderers.
• Recommended workflow for chart-specific customization (e.g. tweaking colors) is to export code from safetyGraphics and then customize it directly (but this isn't well documented)
• There are a few functions in safetyCharts that make this easier for some charts, but not for all renderers. (This is a good intro level task to make more of these)
• If we want to support chart-specific customizations in the safetyGraphics app, I think those settings should live on the chart page for the chart being tweaked.
• I'm honestly not sure if there is a good way to work around this right now without updates in a renderer.
  • @samussiah - Any idea if we can customize colors via some funky initialization with custom mapping etc?
• We should consider adding an FAQ summarizing this.
• Additional development could make this easier. Having a pop-up on the chart page that lets a user customize the chart config would be great ...
• We've created "chart maker" applications like this in the past - like this one, but we've never done this in safetyGraphics/Shiny.
• I know there are existing Shiny applications that do things like this, but not sure how well they fit our use case (Googling "Shiny Chart Maker" and seeing whats out there would be a good task for someone)
• Would be cool to allow for this level of customization via a config parameter in the chart yaml. It could point to some kind of schema (That's what the example above did IIRC) or just list out the configurable settings for a chart and then set up a basic UI with one text box per option that the user can tweak.

cc: @samussiah @nandriychuk @bzkrouse in case they have any thoughts on how to move forward on this.

[samussiah]

IIRC webcharts has color_by (generally already set within the renderers) and colors (generally not set in renderers > default colors). We can theoretically update the R functions to pass along colors via ......