Add an option to censor small values appearing in tables via a threshold

[HarrisonWilde]

Аs mentioned in this old issue: #76 (comment) it would be very useful to be able to add some censoring cut-off at which point only < N or ** or similar is shown to indicate the number is smaller than some threshold. This is a very common situation in medical and other sensitive settings where this package sees widespread usage. Happy to attempt to implement if there is some support on getting to grips with the code. I would imagine this would be a quick fix but I don't have the bandwidth to fully dive into the package so would be good to talk to a maintainer.

Thanks!

[tomlincr]

+1 for this!

[tomlincr]

Possible inspiration, solutions or alternatives:

• https://github.com/sdcTools/sdcTable
• https://github.com/statisticsnorway/easySdcTable (easy interface for sdcTable)
• https://github.com/sdcTools/sdcMicro (? shiny interface for sdcTable)