`HKClinicalRecord` exposure

[AliakseiT]

Is your feature request related to a problem? Please describe.
As a developer working with Apple Health Kit, I shall be able to access clinical records (e.g. medication records) via HKClinicalRecord

Describe the solution you'd like
Expose HKClinicalRecord and fhirResource in HealthKitReporter (and later on health_kit_reporter wrapper in Flutter)

Additional context
Apple requires a specific addition in the profile for the Clinical Record type

[quentinleguennec]

@AliakseiT I created a PR that gives access to Clinical Records, it's still early in the testing process but you can have a look and let me know if you encounter any issue with this new version:
#25

[AliakseiT]

Thanks @quentinleguennec. We, however, moved to a thiner wrapper https://pub.dev/packages/flutter_health_kit, which has solved the underlying thread issues like kvs-coder/health_kit_reporter#68 or kvs-coder/health_kit_reporter#58

It does not have the support for Clinical Records yet.