Nicer table formatting in vignette and `report_stats()` output

[mdingemanse]

Right now report_stats() outputs something that looks like this in the knitted vignette:

This isn't all that readable and doesn't look great. What are our options for creating more readable, side-scrollable tabular output formats in an R vignette? Perhaps @PabRod has ideas?

[PabRod]

I think kableExtra is the package you need.

[mdingemanse]

I'll need to dig into the report_stats() function for this, as that is the one outputting both the summary stats and a table. Following the logic we used for the graphics we probably want to expose those two parts separately too, do you agre @bvreede?