Improve performance in CheckboxTree

[jernestmyers]

A noticeable performance hit resulted when switching from the legacy WDKClient CheckboxTree to the new version here in CoreUI. The performance hit is most noticeable in Microbiome and genomics wherein the rendered nodes are in the thousands. The profiler suggests the extensive use of inline styles and the thousands of Tooltip instances are largely contributing to this performance hit.

Possible ideas to improve the performance is twofold:

• "Lift up" inline styles to the parent as suggested in bullet 2 of Emotion's performance docs
• Roll out a tooltip that will use a single instance and that leverages event delegation

[dmfalke]

We should also look at https://www.npmjs.com/package/react-vtree.