Draco: add variants (#10925)
Draco: add variants (#10925)

* Draco: add variants

+ This package has many optional build dependencies that were not registered in
  older versions of this recipe.  I've added (and tested) this more complete
  list of optional dependencies: parmetis, superlu-dist, qt.

* fix style issues

LLNL/spack,iulian787/spack,LLNL/spack,iulian787/spack,LLNL/spack,LLNL/spack,iulian787/spack,iulian787/spack,LLNL/spack,iulian787/spack