Fix ClassCastException in cql-to-elm-cli with modelinfo

[dehall]

This PR fixes #1803 - a ClassCastException when running the CLI and specifying a modelinfo.

The short explanation is that in Kotlin, unlike Java, anonymous lambdas cannot be cast to interfaces unless they are explicitly marked as functional interfaces (fun interface). So an alternative fix would be to mark ModelInfoProvider as a functional interface, but that may have broader implications. This approach instead creates an anonymous class that explicitly implements the interface.

To test this, run the cli and specify a modelinfo, eg here's an example with files already in the repo:

./gradlew :cql-to-elm-cli:installDist
./cql-to-elm-cli/build/install/cql-to-elm-cli/bin/cql-to-elm-cli  --model ./quick/src/main/resources/org/hl7/fhir/fhir-modelinfo-4.0.1.xml --input ./cql-to-elm/src/jvmTest/resources/org/cqframework/cql/cql2elm/fhir/r4/TestBundle.cql

[dehall]

Apologies, I'm pretty sure the CI is all failing because this PR comes from a fork but I'm not sure what to do about it. I'm open to suggestions

[antvaset]

@dehall Looks good to me 👍 The PR only needs another approval and then it can be merged.