Don't apply effects in WorkflowRenderer

In terms of consistency, those effects should be applied in TrackHandler, not in WorkflowRenderer. There are two reasons for it.

1) We only save all the information of the timeline in Workflow to Project
2) In terms of separation. If we seperate Workflow from Renderer to establish IPC in the future, Renderer should just be a class to display frames/audio given by Workflow.

Signed-off-by: Hugo Beauzée-Luyssen <hugo@beauzee.fr>