Show warning for active incidents

[aschiavo]

Change Summary

This change adds a background task that queries status.flyio.net for unresolved incidents for every command.

If any incident is returned, it will show a warning to the user. The warning includes instructions to either check statuspage or execute the specific command for listing the incidents which provides extended information.

How:

• Adding a background task that is enqueued from a common preparer so it's executed for every command. It can be disabled by setting FLY_NO_INCIDENTS_CHECK env var to a truthy value. The check is ignored for the more specific incidents list command.
• Adding a incidents list command which will provided detailed information about the unresolved incidents.

Documentation

• [ ] Fresh Produce
• [ ] In superfly/docs, or asked for help from docs team
• [x] n/a

[dangra]

Oh, the only other thing is making DeepSource check pass:

https://app.deepsource.com/gh/superfly/flyctl/run/c0d3a878-c5b7-4f6a-a27f-c15b02a9eb42/go/