Refactor vtk-m symbol visibility macros to be more consistent.

Instead of labeling each method that needs to have visibility
we can label entire classes.

Lastly the CMake generated export macro functionality would break
if we every tried to generate export macros from the cont or exec
directory, as those defines already exist to label device/host code.
That is why we have setup generate_export_macro to use a different
pattern for the names of our exports.
347 jobs for refactor_vtkm_symbol_vis_controls