Clean up SMTK build

[vibraphone]

The addition of smtk::mesh has resulted in a lot of build cruft that needs to get cleaned up:

• CMake options that should be marked as advanced, including:
  ENABLE_{CGM,CGNS,HDF5,IGEOM,IMESH,METIS,MPI, ...} and MOAB_BUILD_{DAGMC,HEXMODOPS,MBCHACO,MBCONVERT, ...}.
• Warnings in thirdparty/MOAB should be disabled.
• Things like VTK support in MOAB should probably be turned on (especially when SMTK's VTK support is enabled).

[vibraphone]

@robertmaynard For your consideration. 😄