Apply doc standards for ReadtheDocs builds

Applies the following changes:
add version number to documentation left navigation bar and page title
add an "About" section with a license page
enable htmlzip, pdf, epub formats when publishing on Read the Docs
set pdf title, author, copyright, and version
rename .sphinx/.doxygen to sphinx/doxygen
remove docBin from URL
update rocm-docs-core dependency

Change-Id: I947cf32cd42d9f4e55b1ddd324ad4a7e4ba3f3e3

runtime/docs/sphinx/_toc.yml.in

@@ -0,0 +1,12 @@
+# Anywhere {branch} is used, the branch name will be substituted.
+# These comments will also be removed.
+root: index
+subtrees:
+  - numbered: False
+    entries:
+    - file: structure
+    - file: api
+    - file: environment_variables
+  - caption: About
+    entries:
+    - file: license