Add ALIGN to transformers (#21741)

Adds the ALIGN model to transformers. ALIGN is introduced in "Scaling Up Visual and Vision-Language Representation Learning With Noisy Text Supervision" by Chao Jia, Yinfei Yang, Ye Xia, Yi-Ting Chen, Zarana Parekh, Hieu Pham, Quoc V. Le, Yunhsuan Sung, Zhen Li, Tom Duerig.

docs/source/en/_toctree.yml

@@ -540,6 +540,8 @@
       title: Audio models
     - isExpanded: false
       sections:
+      - local: model_doc/align
+        title: ALIGN
       - local: model_doc/altclip
         title: AltCLIP
       - local: model_doc/blip