TrigHTTSGInput, MT fixes, runnable example
This MR is a follow-up of !51380 (merged):
- all data is read through the handles
- defaults are set to read ITk data
- threading issues are fixed (the algorithm is not runnable in parallel and there is no intention to make it so because of ROOT tree creation involved)
- small renaming of methods for consistency
- JO is prepared that allows to run of this code as part of the transform
- README file added explaining how to run
Edited by Tomasz Bold