[WIP] Support loading cached QCPortal datasets

[j-wags]

see https://github.com/MolSSI/QCFractal/pull/802)

Description

Provide a brief description of the PR's purpose here.

Todos

Notable points that this PR has either accomplished or will accomplish.

• [ ] TODO 1

Questions

• [ ] Question1

Status

• [ ] Ready to go

[j-wags]

Superseded by #284