Modify script to build the website

[LucieContamin]

As the package is named gamar, we don't need to keep to website generator script that was removing the Bioconductor link. However, the script also contains code to remove unwanted output folders generated by the examples...
The script should be updated to all the examples and remove all the unwanted output folder generated (for example predator-prey) and should also be renamed into cleaning_output_website.

[choisy]

I opened an issue on pkgdown here to see whether they can fix this problem directly in pkgdown. Let's first see what they answer.

[choisy]

The pkgdown developers suggest that we simply put \dontrun{} is the example. Would it be a problem if we do that?

[LucieContamin]

If we do that, none of the examples will be run. So we will just have lines of code, no results to show the behavior of our package.