add shared experts for upcoming Granite 4.0 language models (#35894)

* Modular GraniteMoE with shared Experts.

Signed-off-by: Shawn Tan <shawntan@ibm.com>

* Modified

* Import order.

* Modified for style

* Fix space.

* Test

* Remove extra granitemoe file.

* New converted file and tests

* Modified __init__ files.

* Formatting.

* Dummy PT objects

* register granitemoe shared model

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* fix linting of a file

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* fix import in modeling file

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* update generated modeling file

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* add documentation

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* update docstrings

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* update generated modeling file

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* fix docstrings in config class

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

* merge main

Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>

---------

Signed-off-by: Shawn Tan <shawntan@ibm.com>
Signed-off-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>
Co-authored-by: Shawn Tan <shawntan@ibm.com>
Co-authored-by: Shawn Tan <shawn@wtf.sg>
Co-authored-by: Sukriti-Sharma4 <sukriti.sharma4@ibm.com>
Co-authored-by: Sukriti Sharma <Ssukriti@users.noreply.github.com>

docs/source/en/index.md

@@ -173,6 +173,7 @@ Flax), PyTorch, and/or TensorFlow.
 |               [GPTSAN-japanese](model_doc/gptsan-japanese)               |       ✅        |         ❌         |      ❌      |
 |                       [Granite](model_doc/granite)                       |       ✅        |         ❌         |      ❌      |
 |                  [GraniteMoeMoe](model_doc/granitemoe)                   |       ✅        |         ❌         |      ❌      |
+|            [GraniteMoeSharedMoe](model_doc/granitemoeshared)             |       ✅        |         ❌         |      ❌      |
 |                    [Graphormer](model_doc/graphormer)                    |       ✅        |         ❌         |      ❌      |
 |                [Grounding DINO](model_doc/grounding-dino)                |       ✅        |         ❌         |      ❌      |
 |                      [GroupViT](model_doc/groupvit)                      |       ✅        |         ✅         |      ❌      |