Cross tabulations

[mountainMath]

Cross tabulations for 2021 are easily available via the {cansim} package. Cross tabulations for the 2016 and earlier censuses come as CSV or XML files, and can be processed through the experimental statcanXtabs package. It would be nice to clean up/formalize the xtab package and either incorporate it directly into the {cancensus} package or alternatively clean it up and link to it as a standalone package.