Reduce charts bundle size

[timroes]

Did some investigation. The easiest way to save some bytes is to not require the color package in the main bundle.

This is where it's used:

MappedColors
-> palettes (charts)
-> LegacyColorsService
   -> ChartsPlugin (setup/start)
      -> initVisConfig (Vis) vislib
         -> render (Vis) vislib  async!
         -> render (VisController) vislib async!
lightenColor
-> palettes (charts)
-> ColorPicker (charts)
   -> getColorPicker (vis_type_xy)
      -> VisComponent (vis_type_xy) react component
         -> xyVisRenderer.render (vis_type_xy) async!
   -> getColorPicker (vis_type_pie)
      -> PieComponent (vis_type_pie) react component
         -> getPieVisRenderer (vis_type_pie) async!
-> getLayers (vis_type_pie)
      -> PieComponent (vis_type_pie) react component
         -> getPieVisRenderer (vis_type_pie) async!
createColorPalette doesn't actually need the color package

Plan:

• Lazy load legacy color service (getLegacyColorService: Promise on contract instead of instance)
• Resolve in render method of VisController in vislib and pass down to initVisConfig
• Pass this service getter into PaletteService - resolve there in getPalettes and pass to buildPalettes (use sync in there)

---

• Remove static export lightenColor
• Turn into getLightenColorService: Promise on contract)
• Pass this service getter into PaletteService - resolve there in getPalettes and pass to buildPalettes (use sync in there)
• Resolve getLightenColorService in getPieVisRenderer and in xyVisRenderer - pass down from there through component to getColorPicker and getLayers in sync way

---

• Make ColorPicker a lazy component which is exported statically (handles async-ness in react)

---

• Inline small helper to turn hsl into hex (it's just a couple of lines instead of the whole color package)

Will probably save between 30 and 40%

Extracted from #103749

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)