Enforce public API documentation

Add Rake task to police API documentation. Fail the Rake build with
statistics and list of undocumented objects if the API is not 100%
documented, but output statistics in the successful case.

Suppress the statistics in the yardoc task to avoid duplicate output.

Add missing public API documentation

[#55005634]
Merge 55005634-public-API-check to master

[Completes #55005634]