Chart tooltip enhancements

[hughess]

• Add more columns to the tooltips for <ScatterPlot/> and <BubbleChart/>
  • These should include at least one identifier column (e.g., Product Name)
  • The right behaviour might be to include all columns from the query result in the tooltip to start, then provide an option to exclude specific columns
  • If we add these options, we should probably also include a prop where you can specify exactly which column(s) you would like to appear in the tooltip
• Add back the feature to sort tooltip series based on value (max on top of list, min at bottom)
  • #327 breaks the behaviour of multi-series line chart tooltips, where the tooltip would reorder the series shown in the tooltip to match the position of the series at that point in the chart (max on top, min on bottom)
  • To add this functionality back, we will need to add a sort function to the formatter definition
• Make histogram tooltip support multiple series
  • Histogram tooltips work well for a single series, but when we add the ability to plot multi-series histograms, we will need to revisit the tooltip design and examine the data structure that ECharts returns to our component
• Axis title override behaviour
  • You can change the label that appears for the x-axis or y-axis on your chart, but at the moment these labels do not replace the column titles shown in the tooltip
  • For example, if a column name is gdp_usd, it will be formatted as "Gdp ($)".
  • You can override the axis label to show "GDP", but the tooltip will still show "Gdp ($)"

[hughess]

tooltipTitle implemented for scatter and bubble charts in #399