[ROCDOC-95] Standardize documentation for ReadtheDocs

Apply the following changes to project documentation for ReadtheDocs:

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
update dependabot config

Change-Id: Ife8c89a2e9323f436b3e54ef2a9e013c19b3b228

docs/doxygen/.gitignore

@@ -0,0 +1,2 @@
+html/
+xml/