Config/ fields in DESCRIPTION

[Bisaloo]

Prompted by a discussion with @TimTaylor on slack. As far as we know, there is no central place documenting all existing Config/ fields

Here are some Config/ I know:

• Config/Needs/* in pak
• Config/testthat/edition, Config/testthat/parallel, Config/testthat/start-first in testthat
• Config/usethis/last-upkeep by usethis
• to be completed

[jamesmbaazam]

Config/Needs/website