remove reg_confidence

[davidoesch]

reg_confidence not needed for dx dy via arosics.
When using external coreg, we don't have reg_confidence band.

Describe the solution you'd like
in case coRegistrationPrecalculated is True, we need to adapt s2_sr and satromo_publish to not export the reg_confidence band

Describe alternatives you've considered
just let a band with 0... consumes disk space ...