Rocm-docs-core

BREAKING CHANGE

- users of the non-legacy API have to set `html_theme` to `rocm_docs_theme` to maintain the current behaviour.

Fix

- **legacy**: fix builds without doxygen
- **extension**: no longer set the html_theme by default in the extension
- **legacy**: restore custom theme on readthedocs

Feat

- move automatic doxygen and doxysphinx to an extension
- move core settings to a sphinx extension

Fix

- restore cookie permissions / analytics script

Refactor

- various formatting and type fixes in util.py

Fix

- various stlysheet fixes

Fix

- update links in header and footer (87)