feat: `KillSignalController`

[dsherret]

import $, { KillSignalController } from "...";

const controller = new KillSignalController();
const signal = controller.signal;

const promise = Promise.all([
  $`sleep 1000s`.signal(signal),
  $`sleep 2000s`.signal(signal),
  $`sleep 3000s`.signal(signal),
]);

$.sleep("1s").then(() => controller.kill());

await promise; // throws after 1 second