TrigConfIO: fix producing JSON files from CA pickles
Support both legacy and CA pickle files when producing the job options JSON file. Also improve the executable to be able to run on both pkl and JSON files.
@smh, in principle this could have avoided some of your changes in !60461 (merged). But I think it's OK to have the confTool not depend on TrigConfIO as the use-cases are very different.
Relates to ATR-26800.