R4epis: adding to {gtsummary} to simplify {epibuffet}

[mjrolland]

We would like to retire the tab_* functions in {epibuffet} in favour of using {gtsummar} functions. The only thing missing is {gtsummary} which we have implemented in epibuffet::tab_univariate is the possibility of producing stratified estimates (e.g. mantel hanszel odds ratios). It would be super helpful if someone could pr a function to {gtsummary} add this option.
This has been requested in this issue already and will post there too now to see if they might take it up.
The r4epis tab univariate function is here

[impact: This would help in simplifying and finalising r4epis and get it all on to CRAN quicker with less hastles and less longterm maintenance. ]
[originally proposed by @aspina7]
[suggested repo: https://github.com/R4EPI/epibuffet | @zkamvar]
[additional notes: ]