Add a basic what's new list to the tutorials homepage (#1883)

* Add a basic what's new list to the tutorials homepage

* added GA parameters

Author: holly1238

index.rst

@@ -1,5 +1,14 @@
 Welcome to PyTorch Tutorials
 ============================
+
+What's new in PyTorch tutorials?
+
+* `Introduction to TorchRec <https://pytorch.org/tutorials/intermediate/torchrec_tutorial.html?utm_source=whats_new_tutorials&utm_medium=torchrec>`__
+* `Getting Started with Fully Sharded Data Parallel (FSDP) <https://pytorch.org/tutorials/intermediate/FSDP_tutorial.html?utm_source=whats_new_tutorials&utm_medium=FSDP>`__
+* `Customize Process Group Backends Using Cpp Extensions <https://pytorch.org/tutorials/intermediate/process_group_cpp_extension_tutorial.html?utm_source=whats_new_tutorials&utm_medium=cpp_ext>`__
+* `Forward-mode Automatic Differentiation <https://pytorch.org/tutorials/intermediate/forward_ad_usage.html?utm_source=whats_new_tutorials&utm_medium=forward_ad>`__ (added functorch API capabilities)
+* `Real Time Inference on Raspberry Pi 4 (30 fps!) <https://pytorch.org/tutorials/intermediate/realtime_rpi.html?utm_source=whats_new_tutorials&utm_medium=rpi>`__
+
 .. raw:: html
 
     <div class="tutorials-callout-container">