Import datasets and documentation from epidatasets

[nmdefries]

Checklist

Please:

• Make sure this PR is against "dev", not "main" (unless this is a release
  PR).
• Request a review from one of the current main reviewers:
  brookslogan, nmdefries.
• Makes sure to bump the version number in DESCRIPTION. Always increment
  the patch version number (the third number), unless you are making a
  release PR from dev to main, in which case increment the minor version
  number (the second number).
• Describe changes made in NEWS.md, making sure breaking changes
  (backwards-incompatible changes to the documented interface) are noted.
  Collect the changes under the next release number (e.g. if you are on
  1.7.2, then write your changes under the 1.8 heading).
• See DEVELOPMENT.md for more information on the development
  process.

Change explanations for reviewer

Reexport datasets from epidatasets, inheriting all associated documentation. Add data attribution -- since license info is included in dataset documentation, this is just adding data contributors to DESCRIPTION.

Supersedes #344

Closes #327

[nmdefries]

Failing document is because the epidatasets version on main doesn't export all of the same data objects.

[nmdefries]

This also needs to rebuild docs and add doctor-visits attribution to the DESCRIPTION, once we have that from Roni.

[brookslogan]

Pushed some tweaks; please

• double-check tweaks

Only blocker to merging:

• double-checking whether correlation vignette changes were intentional/okay. If they weren't intentional & you want me to check if changes are okay, please ping me / re-request review.

Others comments are ideas for the future; could you refile to issues if you think it makes sense? Not sure what doc overhaul is going to look like.

[brookslogan]

Wait, there is also

• Update DESCRIPTION and NEWS.md given PRs that have been merged. Version should be 0.9.{x+1} but changelog additions will go under NEWS.md's 0.10 heading.

[nmdefries]

This now depends on cmu-delphi/epidatasets#5

[brookslogan]

Added a bit more to the NEWS.md entry; merging.

[brookslogan]

Trying to fix up CHECKs now.

[brookslogan]

We inherit some soft CHECK complaints from cmu-delphi/epidatasets#10 but I'm going to go ahead and merge.