Add a non-gratis/paid application note for software that requires payment to use.

This is mostly to avoid mass downvoting of software that requires a non-gratis license to use.

In this pic we can see the mess that is the comments section of VintageStory, non-gratis proprietary game with viewable source code for modders and whatnot. Not only are the reviewers annoyed, but people might actually avoid the game because of the low score. And I think that is unfair to the devs.