Transfer some canonical datasets under an organization namespace
As discussed during our @huggingface/datasets meeting, we are planning to move some "canonical" dataset scripts under their corresponding organization namespace (if this does not exist).

On the contrary, if the dataset already exists under the organization namespace, we are deprecating the canonical one (and eventually delete it).

First, we should test it using a dummy dataset/organization.

TODO:
- [x] Test with a dummy dataset
  - [x] Create dummy canonical dataset: https://huggingface.co/datasets/dummy_canonical_dataset
  - [x] Create dummy organization: https://huggingface.co/dummy-canonical-org
  - [x] Transfer dummy canonical dataset to dummy organization
- [ ] Transfer datasets
  - [x] babi_qa => facebook
  - [x] blbooks => TheBritishLibrary/blbooks
  - [x] blbooksgenre => TheBritishLibrary/blbooksgenre
  - [x] common_gen => allenai
  - [x] commonsense_qa => tau
  - [x] competition_math => hendrycks/competition_math
  - [x] cord19 => allenai
  - [x] emotion => dair-ai
  - [ ] gem => GEM
  - [x] hendrycks_test => cais/mmlu
  - [x] indonlu => indonlp
  - [ ] multilingual_librispeech => facebook
    - It already exists "facebook/multilingual_librispeech"
  - [ ] oscar => oscar-corpus
  - [x] peer_read => allenai
  - [x] qasper => allenai
  - [x] reddit => webis/tldr-17
  - [x] russian_super_glue => russiannlp
  - [x] rvl_cdip => aharley
  - [x] s2orc => allenai
  - [x] scicite => allenai
  - [x] scifact => allenai
  - [x] scitldr => allenai
  - [x] swiss_judgment_prediction => rcds
  - [x] the_pile => EleutherAI
  - [ ] wmt14, wmt15, wmt16, wmt17, wmt18, wmt19,... => wmt
- [ ] Deprecate (and eventually remove) datasets that cannot be transferred because they already exist
  - [x] banking77 => PolyAI
  - [x] common_voice => mozilla-foundation
  - [x] german_legal_entity_recognition => elenanereiss
- ... 

EDIT: the list above is continuously being updated