Update itl template to version 2.6

Pierre Dell'Ovarequested to merge
itl-template-2.6 into main

see title.

Diff :

Comment of max N despiking value corrected
Add the Dark After
NPE max put to 255
Add the new spectral mask MAJIS_DEFAULT_SPECTRAL_MASK_shift3
Edited by Pierre Dell'Ova

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