Faceting: Fully implement FacetedPlot component

[bobular]

Subtask to VEuPathDB/web-eda#635

Continues work on #162

• decide on subplot size
• make simple story for each plot type (PiePlot is done)
• minimise margins within subplots (
• minimise spacing between subplots (and get rid of temporary dotted outline)
• render entire faceted plot in the drop-shadow border (not each plot)
• fixed width and simple browser-based horizontal scroll bar
• titles (showing facet.value) may need ellipsis support for long values

Optional for build 55

• click-on-plot to an enlarged modal
• "No data" facet styled differently (perhaps the title has a grey background)

[dmfalke]

Most of this work is actually being done in web-eda. When we have some more time, we will move much of this work to web-components, as plot-specific variants of FacetedPlot.

[nkittur-uga]

Faceted plots look good.