Add pt counts to covariate table 1

[msuchard]

We should update the code to log counts (as well as percentages) of covariates for Table 1s (may need to update LEGEND data model); several journal guidelines have "insisted" on these numbers.

[schuemie]

Well covariate mean/proportion is rounded to 3 digits, which we could multiply by the overall cohort size to get a count with 3 digits of precision.

If we want more precision, we'd need to rerun the export at the participating data sites.

I would prefer to spend my time on more meaningful things. Is this absolutely necessary?

[msuchard]

No re-run. This seems like an (almost) necessary enhancement for the next LEGEND indication.