LFM2 (#39340)
* [modeling][lfm2] LFM2 model on 4.53.0 interface
* [configuration] hook in LFM2 keys
* [modeling][lfm2] update modeling interface for 4.53.1
* [modeling][lfm2] apply mask to hidden conv states
* [misc] ruff format/lint
* [modeling][lfm2] minor: NotImplemented legacy cache conversion
* Create lfm2.md
* create nice modular
* style
* Update modeling_auto.py
* clean and start adding tests
* style
* Update test_modeling_lfm2.py
* Update __init__.py
* small test model size
* config
* small fix
* fix
* remove useless config attrs -> block_dim and conv_dim are hiden_size
* fix prepare inputs
* fix config
* test
* typo
* skip tests accordingly
* config docstrings
* add doc to .md
* skip config docstring check
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Co-authored-by: Maxime Labonne <81252890+mlabonne@users.noreply.github.com>
Co-authored-by: Cyril Vallez <cyril.vallez@gmail.com>
