MLECO-6350: Add code coverage to modules
- Add code coverage for C++ layer
- New cmake utility to enable code coverage flags for GCC compiler
- Use cmake_dependent_option for ability to set ENABLE_COVERAGE only for Debug builds
Signed-off-by: Fernando Barreto Rodrigues fernando.barretorodrigues@arm.com Change-Id: I392354d018b4ab724bd8fbef790d3252ee7d5276