Consider using crandb for package metadata / DESCRIPTION file retrieval

[kevinushey]

For example, to obtain the DESCRIPTION file associated with dplyr 1.0.0, one could query:

https://crandb.r-pkg.org/dplyr/1.0.0

This might be useful for building a deployment manifest in the scenario where a project contains an renv.lock lockfile, but does not have the requisite installed packages available.

[kevinushey]

Alternatively, we could use the cran GitHub mirror; e.g.

https://raw.githubusercontent.com/cran/dplyr/1.0.0/DESCRIPTION

[soetang]

I understood on Dave that this was related to the issue I reported on #1046 . If this becomes the solution i just want to make the point that we use an internal package manager (Posit package manager), and we might not have internet access from all our servers. So it should be possible to point to an internal package manager.