Add llama4 (#3145)

* initial changes

* Add support for other vlm

* cleanup comment

* Improve attn_implementation

* Add comments for support of models

* add model

* add model

* fixes and improvements

* update docker

* Add cache position

* Add tests

* remove redundant changes

* remove tr version

* Upgrade doc + fix linting.

* Fixing the CI.

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Co-authored-by: Nicolas Patry <patry.nicolas@protonmail.com>