temporary changing difficulty intervals in workers
Currently we have a queue that isn't able to reduce for at least a couple of days
![image](https://github.com/huggingface/datasets-server/assets/5564745/646f5fa7-270a-498f-b9c4-32a464d2d8da)

The current difficulty distribution is:
```
Atlas atlas-x5jgb3-shard-0 [primary] datasets_server_queue> db.jobsBlue.aggregate([{$match:{status:"waiting"}},{$group:{_id:{difficulty:"$difficulty"},count:{$sum:1}}},{$sort:{count:-1}}])
[
  { _id: { difficulty: 70 }, count: 3290 },
  { _id: { difficulty: 90 }, count: 501 },
  { _id: { difficulty: 50 }, count: 327 },
  { _id: { difficulty: 60 }, count: 19 }
]
```

I will try to see if changing the worker max/min difficulty helps reducing the load.
temporary changing difficulty intervals in workers: Currently we have a queue that isn't able to reduce for at least a couple of days
![image](https://github.com/huggingface/datasets-server/assets/5564745/646f5fa7-270a-498f-b9c4-32a464d2d8da)

The current difficulty distribution is:
```
Atlas atlas-x5jgb3-shard-0 [primary] datasets_server_queue> db.jobsBlue.aggregate([{$match:{status:"waiting"}},{$group:{_id:{difficulty:"$difficulty"},count:{$sum:1}}},{$sort:{count:-1}}])
[
  { _id: { difficulty: 70 }, count: 3290 },
  { _id: { difficulty: 90 }, count: 501 },
  { _id: { difficulty: 50 }, count: 327 },
  { _id: { difficulty: 60 }, count: 19 }
]
```

I will try to see if changing the worker max/min difficulty helps reducing the load.