[EMCAL-566] Added StatAccumulator for fast time calib

[jokonig]

• Standard calibration is based on boost histograms and fitting the time distribution for each EMCal cell
• New, fast, procedure, calculates mean and sigma on the fly and therefore, no fitting is needed.
• StatAccumulators could be stored in ccdb for each run to later calibrate based on multiple runs if needed (for example for the low gain cells above ~16GeV)

[github-actions[bot]]

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