Use font-variant-numeric tabular-nums for table cells, with a font supporting it

[stof]

Currently, the rendering of the table visualization uses the Gotham Rounded SSm A custom font (as almost everything). But this makes it quite hard to compare numbers in the table.

Browsers (except IE and Edge) support the font-variant-numeric CSS property to render numbers in a tabular way (similar to what happens for a monospace font, but only for numbers) for fonts supporting it: https://developer.mozilla.org/en-US/docs/Web/CSS/font-variant-numeric#Browser_Compatibility
This makes the table a lot more readable. But the Gotham Rounded SSm A font does not support that feature. So it would require using a different font for that rendering.

Current rendering:

Rendering with ``font-variant-numeric: tabular-numsapplied on.keen-dataviz-table tbody td`, and disabling the custom fonts (the system fonts are supporting that feature at least on Firefox on Ubuntu where I took that screenshot, but probably also for other OS):

I find the tabular rendering much easier to read to compare the different rows (and that case is precisely the use case described on MDN for that feature btw).