Upgrade cql-execution; Fix VSAC and ts-node config

[mgramigna]

Summary

Fixes #172

This PR exposes the ValueSetResolver class that we use as an export from fqm-execution so it can be used in other libraries (main use case was use of it within a FHIR server). VSAC also changed their base URL recently for the FHIR API so I updated that too. I also updated the ts-node config to no longer require the use of --files option when testing the CLI

New behavior

• Fixes issue brought up in #172 by upgrading the version of cql-execution (actual bug was fixed in https://github.com/cqframework/cql-execution/pull/306 thanks to @cmoesel)

Code changes

• Upgrade cql-execution dependency
• Export ValueSetResolver from index.ts
• Fix canonical URL used for all VSAC requests, and included a link to where that URL is specified in case it breaks again in the future
• Move the ts-node --files option to tsconfig and update docs

Testing guidance

Mainly just make sure the npm run cli command or using ts-node directly works without passing in the --files option. You can test valueset resolution if you want.

[github-actions[bot]]

Coverage report

St.:grey_question:	Category	Percentage	Covered / Total
🟢	Statements	84.9% (+0.01% 🔼)	1962/2311
🟡	Branches	73.46%	1722/2344
🟢	Functions	87.22% (-0.22% 🔻)	348/399
🟢	Lines	85.17% (+0.01% 🔼)	1890/2219

Test suite run success

353 tests passing in 28 suites.

Report generated by 🧪jest coverage report action from 4d285cf2cded50c0b0a441732c3ba4f4e6a42fe6