Gemini3d

Enable MSIS 2.0 option (default is MSISE00). As part of this, we now use HDF5 files stored in the simulation `inputs/` directory. This requires Gemini3D >= 0.8.0. This speeds up and provides better reproducibility vs. the stdin/stdout pipes used before.

* new test reference data, after corrections to PyGemini
* compare_input: also plot_diff
* msis2: use error code 20 to signal not setup
* HDF5 1.12.1 autobuild if needed
* external libs can be static or shared
* fixed array size error in conductivity gradient term
* apply yitmp bounds fix from inputdata branch
* autobuild: allow requested HDF5 version
* rename 'msis20' => 'msis2' for future versions
* modernize/flatten install
* cli: dedupe options meant for interactive from MPI
* add gemini3d.run -features to print enabled features
* update pygemini plot_diff api
* autobuild: ensure lapack/scalapack/mumps stack are consistent
* don't use option(*_external) for libs as that overrides cache
* link objects for robustness
* ubuntu linking with self-build fixed
* ci: add autobuild case
* update all external lib versions (packaging improvements, avoid cache overrides)

* build any/all external libraries as Release by default
* announce disabled tests instead of silently skipping
* add read/write dump test. Correct file dump to be in simulation output directory.
* update h5fortran,nc4fortran to use auto-length character read
* add scripts to build OpenMPI and MPICH

Use xarray to pass data with metadata. We used this originally, then disabled temporarily, and now restored as xarray has become broadly adopted.

* Add metadata to grid
* use proven matGemini getflag logic
* correct transpose of variables on file read

MSIS 2.0 has a known bug causing all-zero output acknowledged by the authors along with our patch applied in Gemini3D.

HDF5 is more easily found on MacOS, particularly with MacPorts and Homebrew, despite the presence of Anaconda Python.

Grid and Neutral enhancements by mattzett

Minor Rearchitect gemini.bin to make amenable for libgemini future work