[query] Automatically break up big spark jobs

[patrick-schultz]

Spark breaks down when a job has too many partitions. We should modify the implementation of CollectDistributedArray on the Spark backend to automatically break up jobs that are above some threshold of number of partitions into a few sequential smaller jobs. This would have a large impact on groups like AoU who are using Hail on the biggest datasets, who currently have to hack around this issue with trial and error.