WorkFlow Performance: Adds a compiled Library cache that survives multiple executions of the evaluator.

[vitorpamplona]

Fixes #[issue number]

Description
Current FhirOperator reloads (and then recompiles) all libraries in every evaluate call, which includes each of the multiple initial expressions in a single questionnaire page. This leads to slow processing of CQL.

This PR adds a basic compiled Library cache that survives multiple executions of the evaluator.

Alternative(s) considered
None

Type
Choose one: Feature

Screenshots (if applicable)

Checklist

• I have read and acknowledged the Code of conduct.
• I have read the Contributing page.
• I have signed the Google Individual CLA, or I am covered by my company's Corporate CLA.
• I have discussed my proposed solution with code owners in the linked issue(s) and we have agreed upon the general approach.
• I have run ./gradlew spotlessApply and ./gradlew spotlessCheck to check my code follows the style guide of this project.
• I have run ./gradlew check and ./gradlew connectedCheck to test my changes locally.
• I have built and run the demo app(s) to verify my change fixes the issue and/or does not break the demo app(s).

[jingtang10]

please add more info for the todo (maybe an github issue or a link to a doc)!