Use Rscript to get build configuration details

Here's a new pull request to the development branch :)

I had a small compilation issue with JASP-Desktop, so I reverted a related patch to be able to test. You obviously don't want to merge that commit.

I tested this with a very small csv file, and it seemed to be able to pass that data to R and get the results back, so that's good!

The R bundle you ship does have a working Rscript. However, it does not know the right paths. Looking into it more closely, it seems to not entirely be configured like you want: there's a lot of hardcoded `/usr` paths in `bin/R` and in `etc/ldpaths`. If we're bundling it ourselves, I think it makes sense to fix that instead of requiring to always run this with certain environment variables. The way to do that is by using `./configure --prefix=<directory>` to configure your R build.

Does this make sense?