Add reference and example on how to create mutliple table while still having numbering to work in bookdown

[cderv]

See rstudio/bookdown#1272 (comment)

It is a combination of https://bookdown.org/yihui/rmarkdown-cookbook/kable.html#generate-multiple-tables-from-a-for-loop
and

• bookdown.org/yihui/rmarkdown-cookbook/knit-expand.html
• bookdown.org/yihui/rmarkdown-cookbook/child-document.html