Support for relperm interpolation parameters per SATNUM

[lilbe66]

Make it possible to use dedicated relperm interpolation parameters per SATNUM, for water-oil and gas-oil relperm. Could name the interpolation parameters by adding the SATNUM number as postfix. Could use a list for command line input?

For some reservoir models it could be useful to allow for one SATNUM moing towards possimistic relperm and another towards optimistic. Current limitiation with only one water-oil and one gas-oil relperm interpolation parameter, seems too strict.

[berland]

This was earlier a feature of Pyscal, but was removed in favour of offloading that task to interp_relperm in subscript:

Context:
#247
#248
#262
https://github.com/equinor/pyscal/releases/tag/v0.8.0

[lilbe66]

Pyscal seems to be a standard now, and most users will not take the effort to change to another script to get this feature, I think. Would be more user-friendly and efficient to have this possibility in Pyscal.

[berland]

interp_relperm is just a wrapper for Pyscal giving you the possibility to provide more complex parametrization via a yaml file. It reads the same pyscal spreadsheet as input for specifying low-base-high.