Update Read the Docs, documentation, and dependabot (#772)

* update documentation

add version number to documentation

rename .sphinx/.doxygen to sphinx/doxygen

enable htmlzip, pdf, epub formats when publishing on Read the Docs

* add noCI label for dependabot PRs

since RTD CI is separate from math lib CI

* update rocm-docs-core to v0.13.4

* update README with link to rocm.docs.amd.com

[ROCm/rccl commit: c3f47853bd]

projects/rccl/.github/dependabot.yml

@@ -6,7 +6,12 @@
 version: 2
 updates:
   - package-ecosystem: "pip" # See documentation for possible values
-    directory: "/docs/.sphinx" # Location of package manifests
+    directory: "/docs/sphinx" # Location of package manifests
     open-pull-requests-limit: 10
     schedule:
       interval: "daily"
+    labels:
+      - "dependencies"
+      - "noCI"
+    reviewers:
+      - "samjwu"