[WIP] Add curvilinear coordinates

[Yurlungur]

LANL has now open sourced the curvilinear coordinates code that @forrestglines developed. I was mandated to open source it on the LANL github, here: https://github.com/lanl/athenapk

This is an MR into athenapk from the branch point Forrest had. I am sure it's horribly out of date. But Philipp, if you'd like to try and bring this into alignment with the current version of AthenaPK, you now can. My apologies for my delay on this. Note that the following should be added to the license for the diff'd files, which I have not done:

 © 2024. Triad National Security, LLC. All rights reserved.

This program was produced under U.S. Government contract 89233218CNA000001 for Los Alamos National Laboratory (LANL), which is operated by Triad National Security, LLC for the U.S. Department of Energy/National Nuclear Security Administration. All rights in the program are reserved by Triad National Security, LLC, and the U.S. Department of Energy/National Nuclear Security Administration. The Government is granted for itself and others acting on its behalf a nonexclusive, paid-up, irrevocable worldwide license in this material to reproduce, prepare. derivative works, distribute copies to the public, perform publicly and display publicly, and to permit others to do so.

[pgrete]

Great, thanks!
Might be most efficient to go through this at the hackathon.

[BenWibking]

To render correctly in VisIt, just convert "spherical" to "Cartesian":
https://visit-sphinx-github-user-manual.readthedocs.io/en/develop/using_visit/Operators/OperatorTypes/Transform_operator.html#coordinate-system-conversion

[BenWibking]

Ok, it builds and is up-to-date with current AthenaPK now.

[BenWibking]

How tested is this?

I tried running the disk_sph.in problem, and some really weird things happen to the pressure field:

disk_sph_pressure.mov

[BenWibking]

Ok, I've fixed it. There was an algebraic discrepancy between the volume factors used in Athena++ and here. It works now:

disk_sph_pressure.mov

[BenWibking]

It looks like the ordering of the coordinates changed for cylindrical at some point, so Parthenon assumes it's R, z, phi, but this PR assumes its R, phi, z. This needs to be fixed.

[BenWibking]

I don't have the capacity to fix the cylindrical coordinates at the moment, and I only need spherical for my problem, so I've extracted spherical into its own PR: #148