Allow raising sound volume above 100%
This helps in 2 cases:
Folks with hearing problems may need this in order to get stuff done with audio.
Some sound drivers/firmware set the 100% volume pretty low, presumably in order to avoid distorted sound. Combined with low-volume recordings, this is problematic: on my laptop, I often need to raise the volume to 120% or higher.
Closes #17322 (closed)