[UI] Request: Show headroom for volume adjustment of audio clips

[oMrSmith]

Commit Hash
8ac191c

Platform
Windows 10

Summary
When adjusting the volume for an audio clip it should show the maximum peak value in brackets.
Example: Volume: 0.00 dB (Peak: -4.6 dB)
This would help when trying to normalize the volume of an audio clip.

Also it would be helpful being able to right click an audio clip and select "normalize audio to -X dB"

Additional Information / Output