Generate audio preview on import for softron

[KillerX]

Test Here: https://mediabanken.brunstad.tv/item/VX-493926/?index=0&search_id=192634&parentPage=search

Current known issues:

• ~MU1, MU2 -> Stereo tracks are silent~
• The extra tracks are imported as "videos" for some reason

[KillerX]

@mulundapm does the multi language preview require image?

[KillerX]

Jana says that it's ok the way it's now (with no picture).