CRAN Lister

Implemented CRAN lister which uses build in API in R to list the packages in JSON format. That JSON string is passed to the lister.py which then extract all the information to create an origin form the JSON passed by the R script.

Here is the short snippet of the complete response of R script https://forge.softwareheritage.org/swh/meta$404 Closes T1709

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Migrated from D1492 (view on Phabricator)