Investigate and setup code coverage reports

[arkivanov]

We need to investigate if there are any existing solutions for MPP.

[CherryPerry]

https://github.com/JetBrains/kotlin-native/blob/master/CODE_COVERAGE.md
https://github.com/JetBrains/kotlin-native/tree/master/samples/coverage

[arkivanov]

Waiting for above to be released