add functionality to create_datastore_script: scrape from R, Python packages

[RobLBaker]

add a parameter to let users describe the code in their github release. If it is an R package or a python library, it should be possible to scrape even more information from the code to feed into DataStore and automate more fields when creating a reference.

[RobLBaker]

closing for now as the R package component is done. python libraries can be a separate issue.