Restructure HLTMenu JSON

Neaten HLTMenu JSON structure for better readability and splitting out streams information. Full example of change to the file on ATR-19837

• HLTMenuJSON.py -> Split Stream information (saves ~1000lines from LS2 MenuJson)
• HLTChain:streams -> now a list of strings
• HLTMenu:streams -> adds access to the properties of all streams
• StreamTagMakerTool and TrigSignatureMoniMT (cc @rbielski ) updated to use the new/changed functions
• TrigConfIO for C++ test and also added streams to python access
• TriggerMenuMT test to new ordered dictionary JSON format (and bug in reporting failures of tests)
• MTCalibPebConfig.py to write in the new HLT Menu format

Separate MR to update the rulebook to be able to read from the updated format: atlas-trigger-menu/TrigMenuRulebook!534

Removing WIP after confirmed there aren't conflicts with work from @tamartin or other suggestions from @tbold

For future MR: add a HLTStream class to TrigConfData, but implementation here to focus on having updated JSON format for next tests at Point1