Make VariantReporting::Command::CreateReport use Genome::Process

This breaks the Trio wrapper, which needs some more refactoring before it can have Genome::Process integration.
If these are not `has_transient_optional` then when `__errors__` is checked you'll still get an error about these not being set even though they're transient. (This would, for instance, prevent any updates being saved to the Process object unless they're filled in first.)