Define sets of R packages

[jorainer]

Define .txt files (within the /R folder) listing R packages that are required for a specific type of analysis and should hence be installed. Ideally, split packages into separate files - for easier maintenance.

[jorainer]

@emmabusarello , maybe, if you have time, you could define an initial set of R packages that might be used for transcriptomics data analysis? I will add some for metabolomics.