Rmd lessons can't be built with subdirectories

[dpshelio]

As explained in rmarkdown's documentatin, a rmakdown site can only generate pages in a flat directory.

A main restriction of this site generator is that it assumes all Rmd documents are under a flat directory (i.e., no pages under subdirectories).

For the translations to be shown on the same webpage I can think of two ways:

1. Change the website generator (e.g., Jekyll). This would be good to keep all the lessons using the same template and same look and feel, but it would require a significant effort from the maintainers.
2. Create static links to the home page of the built version of the translations. This would require that the translations have all the same directory structure and building infrastructure than the original site. (Note that on other lessons, the repositories only contains the content and the tooling of the parent lessons builds all together: the master lesson and its translations).

List of lessons (that I've found so far) affected by this:

• DC: R ecology lesson
• DC: NEON R Remote sensing
• DC: NEON R Tabular time series
• DC: organization-reproduceR-lesson
• DC: R genomics 🗄️
• DC: rnaseq-data-analysis-ARCHIVED 🗄️
• DC: DEPRECATED-R-ggplot2-ecology (Not 🗄️ ❓)
• DC: R-dplyr-ecology-archived (not 🗄️ ❓)

[fmichonneau]

We can update the make script run the rmarkdown command in each of the subdirectories in succession.