Discuss relationship between file handling and launch event

[mgiuca]

@kenchris raised on w3ctag/design-reviews#371 (comment) that we need to discuss this more.

The explainer currently links file handling to WICG/sw-launch through the launchParams variable. But launch event is currently further behind the file-handling spec, and we're likely to try and ship file handling before launch event (it's much simpler).

So we may need to detach it from the launch event, but we still like the idea of launchParams as part of a future launch event. The explainer should make this inter-spec dependency a bit clearer.

[alice]

Back-linking this to TAG review w3ctag/design-reviews#371