Add "HTTP GET $url" query along with trigger

[maltfield]

A user just requested that we add a feature to the BusKill app to query some webpage on trigger.

This could be useful, for example, to trigger remote shutdown of other devices.

[maltfield]

I think the idea of this would be to execute in addition to the other trigger. For lockscreen, I see no issue.

However, for a shutdown trigger, I see an issue with the possibility that shutdown happens too fast before the query finishes. I'm not sure if the user would want to prioritize the URL query before the shutdown.

In the event that the usual trigger may prevent the HTTP query from finishing, I suppose the best thing to do is to:

1. Execute the lockscreen trigger immediately
2. Execute an asynchronous http query in the background
3. Wait a user-configurable timeout for the http query to finish. If it does not finish by the timeout, go ahead and trigger the shutdown trigger

[maltfield]

This reminds me of similar projects, which the user may be interested in reading about:

1. https://github.com/niklasfemerstrand/panic_bcast
2. https://guardianproject.info/apps/info.guardianproject.ripple/
3. https://docs.buskill.in/buskill-app/en/stable/attribution.html#similar-projects

[maltfield]

This is currently blocked by

• Config file support  #16