Call RGMB Mesh Generators from PyGriffinConnect
This MR updates mesh generation in PyGriffinConnect in favor of RGMBMeshGenerators (PinMeshGenerator and CoreMeshGenerator). This has a number of advantages, including:
- Simpler input for mesh generation
- Material-mesh mapping that occurs directly on the mesh itself rather than an explicit mapping in the Griffin [Materials] block
- The griffin options file can be generated as a single step that does not rely on material-block id mapping. Instead, the mesh-material ID mapping will now occur at the mesh generation step.
- Will make assembly / axial-level power postprocessing much simpler down the line
I'm able to obtain the same eigenvalue results for all of the pygriffin_run tests as well as the ABTR tutorial example, so this is a good indication that the meshes generated before and after introducing RGMB mesh generators are identical.