Move Views altering from workbench_access_views_pre_view() to workbench_access_views_default_views_alter()

We alter Views coming from Workbench at runtime to add Workbench Access columns and filters by using workbench_views_pre_view. I think it will be cleaner and more performant to do such altering by using hook_views_default_views_alter. This hook runs when Views builds its cache info about each Views instead of any time a View is used.

This approach will also place the filters and columns in the Views UI, so that if a site builder wants to edit a View, they will see the added columns and filters.

The only downside is that sites already running with overridden Views will no longer be altered and a site might want them to be. I think individual site builders can add these back in if they want them.