jsconfig.json guidance

[jrieken]

• win @egamma
• os x @chrisdias
• linux @isidorn

Make sure that you get guidance to

• create a jsconfig.json when working with JS files
• exclude big subfolders in a large project (>500 files)

[isidorn]

ping @chrisdias this item was accidently not assigned to march, so pinging you so you are aware that we have to test this

[chrisdias]

@isidorn done with testing, biggest thing found was #4254, same problem on OSX.