Add SeamlessM4T v2 (#27779)

* add working convertion script

* first non-working version of modeling code

* update modeling code (working)

* make style

* make fix-copies

* add config docstrings

* add config to ignore docstrings formatage due to unconventional markdown

* fix copies

* fix generation num_return_sequences

* enrich docs

* add and fix tests beside integration tests

* update integration tests

* update repo id

* add tie weights and make style

* correct naming in .md

* fix imports and so on

* correct docstrings

* fix fp16 speech forward

* fix speechencoder attention

* make style

* fix copied from

* rename SeamlessM4Tv2-v2 to SeamlessM4Tv2

* Apply suggestions on configuration

Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

* remove useless public models

* fix private models + better naming for T2U models

* clean speech encoder relative position embeddings

* refactor chunk attention

* add docstrings to chunk attention method

* improve naming and docstrings

* rename some attention variables + add temperature sampling in T2U model

* rename DOCSTRINGS variable names

* make style + remove 2 useless config parameters

* enrich model card

* remove any attention_head reference + fix temperature in T2U

* new fmt and make style

* Apply suggestions from code review

Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

* rename spkr_id->speaker_id and change docstrings of get_char_input_ids

* simplify v2attention

* make style

* Update seamless_m4t_v2.md

* update code and tests with last update

* update repo ids

* fill article name, abstract andauthors

* update not_doctested and slow_doc tests

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Co-authored-by: Arthur <48595927+ArthurZucker@users.noreply.github.com>

utils/not_doctested.txt

@@ -776,6 +776,7 @@ src/transformers/models/sam/modeling_sam.py
 src/transformers/models/sam/modeling_tf_sam.py
 src/transformers/models/sam/processing_sam.py
 src/transformers/models/seamless_m4t/convert_fairseq2_to_hf.py
+src/transformers/models/seamless_m4t_v2/convert_fairseq2_to_hf.py
 src/transformers/models/segformer/configuration_segformer.py
 src/transformers/models/segformer/convert_segformer_original_to_pytorch.py
 src/transformers/models/sew/convert_sew_original_pytorch_checkpoint_to_pytorch.py