As requested in ATR-17076, adding a new script to count messages inside event loop. Summary of the counts per level is printed and saved to JSON. A new step is added in the TrigValSteering framework (ATR-20038) which runs the script and compares the counts to given thresholds. If thresholds are exceeded, this ART test step will return a non-zero code. It will be executed for all Trigger ART tests based on TrigValSteering.
Also removing the predecessor of this script - RunMsgFinder.py from TrigP1Test.