Expand continuous integration tests

[dustinswales]

Currently there are two CI tests. One to run the entire SCM workflow; install software, build the SCM, run the regressions tests, compare results to baselines. There is another small test that tests the current physics code with the overlaying host, ensuring CCPP compliance.

To bring the SCM documentation and the CI tests close together we need to add the following CI tests:

• Build SCM w/o HPC-stack (w3EMC/BACIO/SP libraries individually)
• Build SCM w/ HPC-stack
• Expand gfortran build tests to use more gfortran versions (add to fortran-compiler matrix)
• Add Intel?

[RobertPincus]

@dustinswales, Sergy Kosukhin of the German Climate Computing Center just made the CI for RTE+RRTMGP a thing of beauty You may find some useful examples there, including pre-built containers with Intel compilers + netCDF + Python environments running in containers.

[dustinswales]

@RobertPincus Thanks. This looks nice and slick! I hope to add something similar, so this is a great reference.