Add BeitForSemanticSegmentation (#14096)

* Add first draft

* Make forward pass work

* Improve conversion script

* Add notebook that checks if it works

* Add BeitForSemanticSegmentation to the tests

* More improvements

* Make BeitForSemanticSegmentation consistent with Segformer

* Small bug fix

* Add BeitForSemanticSegmentation to docs

* Make sure model doesn't output hidden states when the user doesn't want to

* Make it possible to convert the large model

* Fix issue

* Fix conversion script for large model

* Add auxiliary_head option to semantic segmentation model

* Apply suggestions from @sgugger's review

* Apply suggestions from code review

* Fix failing test

Co-authored-by: Lysandre <lysandre.debut@reseau.eseo.fr>

utils/check_repo.py

@@ -102,6 +102,7 @@ IGNORE_NON_AUTO_CONFIGURED = PRIVATE_MODELS.copy() + [
     # models to ignore for model xxx mapping
     "SegformerDecodeHead",
     "SegformerForSemanticSegmentation",
+    "BeitForSemanticSegmentation",
     "FlaxBeitForMaskedImageModeling",
     "BeitForMaskedImageModeling",
     "CLIPTextModel",