Revert "[3/3] AudioEffect: Add a stereo widener effect"

This reverts commit b403520be12d31d5e3c5c64c44a4ae0fd4a48539.
Revert "[3/3] AudioFX: Add center frequency param to bassboost"

This reverts commit c72bc2cd185d77e3317efe4b98c352e35f43012c.