Remove sp library in spack-stack-1.9.0 --> spack-stack-2.0.0

[climbfuji]

Is your feature request related to a problem? Please describe.

sp is deprecated and now provided by ip@5 and later. We still provide sp in spack-stack-1.8.0, giving users enough time to transition to ip.

Describe the solution you'd like
No more sp in spack-stack-1.9.0.

Additional context

We need to make sure the applications are updated accordingly.

@climbfuji took care of NEPTUNE and GSIBEC. Also created NCAR/ccpp-physics#1090 and NCAR/ccpp-scm#524.

[AlexanderRichert-NOAA]

The only thing using it is gsibec; I've asked for a release that can use ip (GEOS-ESM/GSIbec#66).

[climbfuji]

This is blocked by GEOS-ESM/GSIbec#69