Many updates to supported Perlmutter compilers

[xylar]

This merge updates the config_machines.xml file frm E3SM to commit 7f7920b

It also updates pm-cpu spack support:

• Updates gnu builds
• Adds intel
• Adds nvidia

This merge also adds pm-gpu support:

• Adds a machine config file that is mostly a copy of pm-cpu
• Adds gnu, gnugpu, nvidia, and nvidiagpu compilers to spack support

[xylar]

Testing

I was able to build spack environments with ESMF, SCORPIO, MOAB and Metis and Parmetis with all 5 compilers (gnu, gnugpu, intel, nvidia and nvidiagpu) on Perlmutter with these changes.

I was only able to build and test Omega and MPAS-Ocean with gnu and intel, so there may still be some debugging to do.