First version translated into Spanish from the firt 5 tutorials in package learnr (referring to the v1 of r4ds book)

[xavidp]

First version translated into Spanish from the firt 5 tutorials in package learnr (referring to the v1 of r4ds book)
I couldn't finish the check package task since for some unknown reason, no pdflatex is available (apparently) even after installing tinytex, or removing tinytex and installing miktex-portable and restarting R each time.

PR task list:

• Update NEWS
• Update documentation with devtools::document()

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[xavidp]

I added also some new translation to the learnr UI into Spanish