refactored PerformanceCounter (#398)

- introduced `PerfEventHandler` RAII class.
- updated utility functions to use ranges.
- replaced recursive calls with fold expressions in `fake_modify`, `fake_read`, and related functions.
- fixed some minor SonarLint complains (e.g. '0l' vs '0L').

Signed-off-by: Ralph J. Steinhagen <[email protected]>