Full model DAGMC faceting via CAD-to-DAGMC

[connoramoreno]

This branch adds support for a fully open-source, freely available DAGMC faceting workflow via CAD-to-DAGMC. This workflow is implemented as an alternative to the Cubit DAGMC faceting workflow.

Changes included in this branch:

• Introduces a new Stellarator.export_cad_to_dagmc method to automate DAGMC model generation via CAD-to-DAGMC and adds it to test and example scripts
• Renames the Stellarator.export_dagmc method, which generates DAGMC models via Cubit, to Stellarator.export_cf_dagmc and updates syntax in test and example scripts
• Removes the InVesselBuild.export_cad_to_dagmc method as it is made redundant by the Stellarator.export_cad_to_dagmc method and removes it from test and example scripts
• Modifies the magnet modeling workflow to store CAD solids in the MagnetSet.coil_solids parameter for future reference

This PR is considered a draft since test runs on full ParaStell geometries are running out of memory on my local machine. That said, CAD-to-DAGMC is able to successfully mesh our simple test geometry.