WebExtension to redirect YouTube to audio-only

Click on the browser button to access the settings. Files can now be limited by seconds or bytes:

• 123: Limit download to the first 123 bytes
• -123: Limit download by chopping down the last 123 bytes
• 123s: Limit download to approximately the first 123 seconds
• -123s: Limit download by chopping down approximately the last 123 seconds