HTTP API: document disable_stats and enable_queue_totals

[dcorbacho]

These query parameters have been present since 2019 (probably 3.8) but weren't properly documented.

Using GET /api/queues?disable_stats=true&enable_queue_totals=true is far more efficient than the standard GET /api/queues and in many cases will suffice for monitoring and operating purposes.

Related to #9437

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