KerasHub: Update Keras IO docs (#1965)

* list all guides on landing page.
Alphabetize model list

* remove KerasCV from side bar

* remove token embedding and add vitdet

* add Mit symbols

* Add vgg symbols

* add sd3 missing APIs

* add base classes

* add image classifier base class and organize alphabetically

* update densenet path

* remove NLP from side bar

* remove guides removed in this PR - #1960

* include getting started guide

* Add back cv and NLP

Author: divyashreepathihalli

scripts/guides_master.py

@@ -60,16 +60,8 @@
     "toc": True,
     "children": [
         {
-            "path": "getting_started",
-            "title": "Getting Started with KerasHub",
-        },
-        {
-            "path": "transformer_pretraining",
-            "title": "Pretraining a Transformer from scratch with KerasHub",
-        },
-        {
-            "path": "upload",
-            "title": "Uploading Models with KerasHub",
+            "path": "classification_with_keras_hub",
+            "title": "Classification with KerasHub",
         },
         {
             "path": "segment_anything_in_keras_hub",