Custom {roxygen} tags

[aspina7]

Could consider adding custom tags to documentation - e.g. could be useful for:

• licensing: datasets could have different licenses to the overall repo, currently written at end of 'description' section, but could add a dedicated bit for this
• versioning: dataset spinoffs that come from the same original (e.g. ebola having different combos in the intro course), currently written at end of 'description' section, but could add a dedicated bit for this
• language: once datasets are translated then we would need to also do documentation in other languages. currently written at end of 'description' section, but could add a dedicated bit for this
• dictionaries: could link to the associated data dictionary documentation

Separately:

• extdata: current process is to have both the original file and an rda version, only the rda versions can have documents as stands, but could extend to not necessarily need to have all files being rda.
  • alternatively - we could just document in the RDA doc what the original file was and then link to the data-raw script used in recoding.