TrigP1Test: Add ROS stats to JSON conversion and more post-processing

1. Enable ROS rate simulation (ATR-19179) in one TrigP1Test test by supplying the ros2robs option
2. Create script which converts ros_hitstats_reject.txt into JSON format and appends the information to extra-results.json
3. Enable extra steps in TrigP1Test post-processing: the new script + those added in !24465 (merged) (except perfmon)

The extra results are input for plots in the new trigger validation webpage (ATR-19241)

As a result, the following file is created by the CalibPeb_build test: extra-results.json

Tagging @dzanzi, @salderwe, @elazzari