[PWGEM,Tools] Update EMCal Conversion ML Model and enable batching of…

[mhemmer-cern]

… ml models

• Add option to use ml models in batches, instead of testing one candidate per call to reduce speed up application of ml models
• Update emcalPhotonMcTask.cxx to incoporate these changes
• Update histograms that will be stored and filled

[github-actions]

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[mhemmer-cern]

Hello @fcatalan92 @fmazzasc
While working on some ML model for EMCal cluster, I tried adding the option to use the ml output in batches. Also looking into model.h it looked to me like there is a potential memory issue where a pointer gets created pointing to a local variable inside the function. After return is called the memory for the variable should be freed making the pointer point to garbage.
Could you please have a look into the changes and the comment made by this commit to the ML code?