Redirecting Former Torchies Tutorials (#3131)

* Redirecting autograd_tutorial_old.
* Redirecting parallelism_tutorial.
* Redirecting nnft_tutorial.
* Redirecting tensor_tutorial_old.
* Redirecting former_torchies_tutorial.
* Removing README as .py files have been changed to .rst.
---------

Co-authored-by: Svetlana Karslioglu <[email protected]>

Author: AlannaBurke

beginner_source/former_torchies/README.txt

@@ -0,0 +1,8 @@
+Autograd
+==============
+
+This tutorial is out of date. You'll be redirected to the new tutorial in 3 seconds: https://pytorch.org/tutorials/beginner/basics/autogradqs_tutorial.html
+
+.. raw:: html
+
+   <meta http-equiv="Refresh" content="3; url='https://pytorch.org/tutorials/beginner/basics/autogradqs_tutorial.html'" />