SPIKE: consider async query execution for athena

[dogversioning]

pyathena provides a non-PEP async cursor that, if used correctly, could greatly accelerate runtime - it would be A Project to get it in, but would allow us to do things like queue several denormalized tables to run at once.

Some things to consider before going down this path:

• How do we mark queries as parallelizable vs dependent?
• How does this impact other databases?
• How big of an overhaul to the existing codebase would this be?

[dogversioning]

This is probably going to introduce too much low level logic to studies - closing as won't do