Add zkalc scripts to develop

[yelhousni]

zkalc branch has some scripts to benchmark gnark-crypto which is now behind develop optimizations #432. Either we can merge this PR to add the scripts to develop (and master) or automate the process so that the branch track develop.

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[yelhousni]

draft for now as the tests need to be cleaned: I forgot that in zkalc branch I got rid of windowed scalar multiplication to bench only GLV scalar mul (the fastest between the two).

[yelhousni]

zkalc branch is up to date with master