Add build option that generates trace log statements

[jwharm]

Add optional log statements that will log all function calls and parameters.

See jextract for example: https://github.com/openjdk/jextract/blob/master/doc/GUIDE.md#tracing

I think it would be ideal to make this an option in the generateSources Gradle task, so the trace log statements won’t exist in “production builds” of java-gi bindings.