[Feature request] Add option for playback speed slider in player

[veivataan]

Checklist

• I have searched for existing issues (open and closed) and confirmed this feature hasn't been requested before
• I believe this feature request will benefit more than 10% of users, not just myself

Feature Description

Tubular has already a working implementation of this. It allows to set one area of the player to be a "tempo"-slider and works remarkably well. This would be a great UX improvement for easy fast forwarding.