Compare other lightweight charting libs to replace plotly.js

[colleenm]

For reports with pie charts displaying quantitative data (example), we use plotly.js to do chart layout.

We've found at least one bug in plotly (title wrapping) we have to work around, and there may be a different charting library that does what we need more straightforwardly.

We'll also want to add bar charts to the UI soon (see #11); a graphing library that has a clean UI for both would be ideal

[colleenm]

Chart layout mostly deprecated. We may bring back something like this in the future but may rebuild it from scratch (including with a better chart library)