Doxysphinx docs (#3192)

* Reorganize documenation based on rocm-docs-core

* Move build, install and contributing guides to docs

* Bump readthedocs config to Ubuntu 20.04

* Add more direct links to the API modules

* Pin rocm-docs-core version, add dependabot

- Use the pip package to have rocm-docs-core pinned
- Add dependabot config to update pinned packages (including rocm-docs-core)

* fixup! Add more direct links to the API modules

---------

.github/dependabot.yml

@@ -0,0 +1,12 @@
+# To get started with Dependabot version updates, you'll need to specify which
+# package ecosystems to update and where the package manifests are located.
+# Please see the documentation for all configuration options:
+# https://docs.github.com/github/administering-a-repository/configuration-options-for-dependency-updates
+
+version: 2
+updates:
+  - package-ecosystem: "pip" # See documentation for possible values
+    directory: "/docs/.sphinx" # Location of package manifests
+    open-pull-requests-limit: 10
+    schedule:
+      interval: "daily"