Change spectrograph names for Keck/KCWI

[kbwestfall]

Given that Keck calls the whole instrument KCWI, I think we should adopt a naming scheme similar to other instruments in pypeit. I.e., change keck_kcwi to keck_kcwi_blue and keck_kcrm to keck_kcwi_red. Thoughts?

[rcooke-ast]

This was discussed a while ago on Slack, and came to the decision that we have currently adopted. That said, I agree with you, and would probably prefer your suggested change, as it also aligns better with how things are named in PypeIt.