[Raster layer zonal aggregation algorithm] add option to store result in spectral library format

[janzandr]

This is a follow up issue for: https://bitbucket.org/hu-geomatics/enmap-box/issues/1406/raster-layer-zonal-aggregation-tools-cant

[vprint]

Thank you for the fix 👍

About this question :

This is an error from myself, i was talking about Samples raster layers values algorythm !