Jet: Migration to Rocky8

[InnocentSouopgui-NOAA]

Jet now runs Rocky8 with its own installation of spack-stack.
For Global Workflow to transition to Rocky8( Refs NOAA-EMC/global-workflow#2377), this module must migrate as well

What are the requirements for the new functionality?

• update jet module file to compile using Rocky8 spack-stack installation.

Acceptance Criteria

The global workflow is able to run in both cycled and forecast-only modes at resolutions up to C384

Suggest a solution (optional)

update modulefiles/prepobs_jet.lua to use rocky8

[InnocentSouopgui-NOAA]

@InnocentSouopgui-NOAA is working on this issue