PerfMonAna: Cleanup legacy code

Alaettin Serhan Meterequested to merge
amete/athena:main-perfmonana-cleanup into main

This MR is a follow up to !75234 (merged) and cleans the legacy PerfMon infrastructure from PerfMonAna.

Related to ATEAM-989

cc: @fwinkl, @tovsiann

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