Use code-coverage.cmake from cmake-scripts #124
Description
Currently, the template just applies -fprofile-arcs -ftest-coverage to the Greeter target from test. As far as I could tell, it doesn't really generate the code coverage data locally, and I think it'd be useful to be able to do that.
The code-coverage.cmake script exposes targets that we can run if we want to generate the data locally too. It also does checks that the current ModernCppStarter solution doesn't.