Run code quality tools as part of CI

Would be nice to get code quality metrics as part of MRs. For now we're running both cppcheck (for granular warnings about code quality) and lizard (which tells when functions are too complex, poorly commented, etc.)

Please let me know if you'd like to use different flags in particular for cppcheck (I know Petr had some opinions already :) ) and if you'd like to run other code quality tools.