This updates the minimal supported version of CMake to 3.16, which in turn enables us to use more CMake features and have a cleaner build system.
This is the version that provides most new features and also the one we use in our latest docker image for CI.
1. Cleanup the README of app_trace_to_host example based on the template.
2. Remove unused header files in the example.
3. Fix typos in public header file.