Allow to always start recording once mixxx starts

[spotlesscoder]

Feature Description

When I'm in a live situation it's sometimes so busy right before I start my set that I forget to press the record button
So I want to have a setting in the recording preferences section where I can enable "Always record once playback starts"
Because it might use a lot of storage when you open mixxx and then have to leave the PC unexpectedly - keeping mixxx running for hours and hours potentially - the functionality from #13911 should be used for this recording behavior so that recording only really happens when there is audio output