Add 404 page (#1933)

* Add 404 page

Only build htmlzip format for docs

* Add homepage link to 404 page

docs/404.md

@@ -0,0 +1,5 @@
+# 404 Page Not Found
+
+Page could not be found.
+
+Return to [home](index) or please use the links from the sidebar to find what you are looking for.

docs/conf.py

@@ -4,10 +4,6 @@
 # list see the documentation:
 # https://www.sphinx-doc.org/en/master/usage/configuration.html
 
-import shutil
-shutil.copy2('../CHANGELOG.md','./')
-shutil.copy2('../RELEASE.md','./')
-
 from rocm_docs import ROCmDocs
 
 docs_core = ROCmDocs("ROCm Documentation")