Scale geometry when making DAGMCUniverse

[shimwell]

Description

Ability to scale DAGMC surface mesh when making DAGMCUniverse. For example if someone makes a CAD geometry meshes it and then exports a h5m file in meters format it would need scaling to get it into cm units needed by OpenMC.

For example if someone sends you a stellarator dagmc.h5m file in meters format 😆

Alternatives

Yes it would also be possible to scale the mesh when produced but assuming you don't have the workflow to remesh or you don't have the CAD then it would be super convenient to scale the geometry when making the DAGMCUniverse.

Compatibility

Compatibility would be the same as default would be to have a scaling factor of 1

[pshriwise]

This should be able to be accomplished with code similar to that which is in place for the MOABMesh class that supports unstructured tet tally meshes.

https://github.com/openmc-dev/openmc/blob/0d4a85d3a81b74c013fc30435870ea3f7ed4eb41/src/mesh.cpp#L2290-L316