"compare-betas" table should show number of installs

It would be able for the table at e.g. https://mozilla.github.io/stab-crashes/compare-betas.html?product=Firefox&beta1=81.0b9&beta2=82.0b2 to display the number of installs for each crash, so we could at a glance see which are single-install signatures, that are likely uninteresting.