WIP: Bump Parthenon version to current `develop` and new B Cleanup w/GMG

[bprather]

This is a testing branch for moving KHARMA back atop Parthenon's develop branch. It seems to break a few minor things, and one major thing: the old BiCGSTAB solver KHARMA leverages for cleaning the magnetic field no longer works with new tasking.

However, Parthenon now has much more powerful geometric multigrid (GMG) solvers, and I've written a new magnetic field cleanup based on them which is faster and seemingly more reliable, but which more importantly supports SMR/AMR grids as we need for resizing INCITE simulations. (Note it doesn't support cell-centered fields, and likely not Dirichlet boundaries either)

Currently this breaks old stuff and is maybe slow, and there's more modernization (type-based variables & packs) that I want to throw in before merging.

If you happen to need to resize a simulation onto an SMR grid, though, this will do it!