feat(ci): add a custom CMake command to run gcovr
Description
The command to run gcovr is long and ugly. These changes add a custom CMake command to run it. This reduces redundancy across project and make it easier to use.
Closes #1074 (closed)
How to test it?
- Run it in a coverage build. It should work correctly, the output should be valid.
- Run it in a non-coverage build. An error message should be displayed.