Add MetaCLIP 2 (#39826)
* First draft
* Make fixup
* Use eos_token_id
* Improve tests
* Update clip
* Make fixup
* Fix processor tests
* Add conversion script
* Update docs
* Update tokenization_auto
* Make fixup
* Use check_model_inputs
* Rename to lowercase
* Undo CLIP changes
* Address comment
* Convert all checkpoints
* Update auto files
* Rename checkpoints
