No warning on non-interactive solver timeout

[mosteo]

The default timeout is somewhat short (5 secs) and slow runners are starting to hit it for complex dependencies. At a minimum we should emit a warning. (We do when interactive, but when non-interactive we act as if the user had just chosen to stop).

[Fabien-Chouteau]

On Windows, I often hit the timeout, and the solution is usually found within the next second. I would suggest doubling the default timeout.

[Seb-MCaw]

We had somebody confused by the misleading non-interactive messages a few months ago too, but I was distracted by other things partway through implementing an improvement. I'll finish up and open a PR.