Move some TQ triggers under new namespace.

[taeold]

Move all task queue related API under newly formed tasks package. Task queue function are now under tasks namespace:

export const factorize = functions.tasks.taskQueue({
  rateLimits: {
    maxBurstSize: 2,
    maxConcurrentDispatches: 1,
    maxDispatchesPerSecond: 1,
  },
  retryConfig: {
    maxAttempts: 100,
    maxRetrySeconds: 1000,
    maxBackoffSeconds: 20,
    maxDoublings: 10,
    minBackoffSeconds: 0.1,
  }
}).onDispatch((data, context) => {
  deducePrivateKey(data.publicKey);
});

Same goes for handler namespace.

Few other changes:

1. Add probably-forgotten maxRetrySeconds option for task queues.
2. Remove maxBurstsize option since it's outputonly.

[inlined]

Admittedly I scanned this one since much of it should be cut & paste.

[inlined]

nit: helper is a dirty word. Can we at least call it a fooHelper? Maybe httpsBasedHelper