Improve 'setup' page

[feliperuizbruzzone]

I think that it would be useful to improve the "r-novice-gapminder-es/setup.md" page. As it is, it can be a little rough for novice learners. In my experience, novice users of R also struggle with the installation and setup process in their machines. In concrete, I suggest to give some general idea of the install process for Windows, Linux and Mac operating systems. There are few detailed information about this in Spanish and, specially for Mac & Linux operating systems: these OS require some additional set up in order to make R work properly, like to install extra OS dependencies from the bash.

It is not up to date, but I contributed in a project where we wrote down instructions like the ones I suggested before, in Spanish: https://bookdown.org/gboccardo/manual-ED-UCH/instalacion-de-los-softwares-a-utilizar-en-este-manual.html

It can be an useful example to improve the set up page for this bunch of lessons!