Explore ways to improve visual speed

[Bergam0t]

Definitely experiencing some issues with load times compared to Typescript-based visuals.

A couple of things to explore here.

https://dataveld.com/2018/11/10/5-performance-tips-for-r-and-python-scripts-in-power-bi/

https://community.fabric.microsoft.com/t5/Desktop/R-visualization-runs-slow/m-p/914330

[Bergam0t]

Started in #36 but this would benefit from further investigation and effort. Still very slow, particularly on PBI service.