Cumulus Library v2.2.0 release

[dogversioning]

You can install the latest library release with pip install -U cumulus-library. The release notes are over on the project github.

This release primarily adds tooling in support of the data metrics study, focused around improving how studies are loaded. It also includes some bugfixes/performance improvements for large table searches, and adds the data metrics and UMLS studies as official build targets.