sanitycheck: Add option to use gcovr for coverage
sanitycheck: Add option to use gcovr for coverage

gcovr is already a dependency in scripts/requirements.txt. The
visualization is different, but the functionality should be the same.
Tested with gcovr 4.2.

Relates to #17626.

Signed-off-by: Christian Taedcke <1d7d3458c4d94e1013a9872dbd5fe0865ba6a124@taedcke.com>

galak/zephyr,Vudentz/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,finikorg/zephyr,nashif/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,galak/zephyr,Vudentz/zephyr,galak/zephyr