Add basic support for Intel Icelake
Created by: TomTheBear
Currently supported counters:
- Fixed-purpose counters without the new FIXC3 (event TOPDOWN_SLOTS)
- PMC counters with all defined events in Perfmon JSON
- Thermal counters
- Voltage counters
- RAPL (energy) counters
Completely untested as I don't have access to an Icelake system.