docs: drop sphinx and use doxygen exclusively (#2932)

.readthedocs.yaml

@@ -3,41 +3,38 @@
 # Read the Docs configuration file
 # See https://docs.readthedocs.io/en/stable/config-file/v2.html for details
 
-# Required
 version: 2
 
-# Set the version of Python
 build:
   os: ubuntu-24.04
   tools:
     python: "miniconda-latest"
-  apt_packages:
-    - libboost-locale-dev  # required for rstcheck in cpp code block
-  jobs:
-    post_build:
-      - find ./third-party -iname "*.rst" -type f -delete  # find and delete rst files in third-party
-      - rstcheck -r .  # lint rst files
-      # - rstfmt --check --diff -w 120 .  # check rst formatting
+  commands:
+    # because we are overriding the build commands, we need to setup the environment ourselves
+    - cat third-party/doxyconfig/environment.yml
+    - conda env create --quiet --name ${READTHEDOCS_VERSION} --file third-party/doxyconfig/environment.yml
+    - npm install "@fortawesome/fontawesome-free"
+    - mkdir -p ${READTHEDOCS_OUTPUT}html/assets/fontawesome/css
+    - mkdir -p ${READTHEDOCS_OUTPUT}html/assets/fontawesome/js
+    - cp node_modules/@fortawesome/fontawesome-free/css/all.min.css ${READTHEDOCS_OUTPUT}html/assets/fontawesome/css
+    - cp node_modules/@fortawesome/fontawesome-free/js/all.min.js ${READTHEDOCS_OUTPUT}html/assets/fontawesome/js
+    - cp -r node_modules/@fortawesome/fontawesome-free/webfonts ${READTHEDOCS_OUTPUT}html/assets/fontawesome/
+    - |
+      wget "https://raw.githubusercontent.com/LizardByte/.github/master/branding/logos/favicon.ico" \
+        -O ${READTHEDOCS_OUTPUT}lizardbyte.ico
+    - |
+      wget "https://raw.githubusercontent.com/LizardByte/.github/master/branding/logos/logo-128x128.png" \
+        -O ${READTHEDOCS_OUTPUT}lizardbyte.png
+    - cp ./third-party/doxyconfig/Doxyfile ./docs/Doxyfile-doxyconfig
+    - cp ./third-party/doxyconfig/header.html ./docs/header-doxyconfig.html
+    - cat ./docs/Doxyfile >> ./docs/Doxyfile-doxyconfig
+    - cd docs && doxygen Doxyfile-doxyconfig
 
 # using conda, we can get newer doxygen and graphviz than ubuntu provide
 # https://github.com/readthedocs/readthedocs.org/issues/8151#issuecomment-890359661
 conda:
-  environment: docs/environment.yml
+  environment: third-party/doxyconfig/environment.yml
 
-# submodules required for include statements
 submodules:
   include: all
   recursive: true
-
-# Build documentation in the docs/ directory with Sphinx
-sphinx:
-  builder: html
-  configuration: docs/source/conf.py
-  fail_on_warning: true
-
-# Using Sphinx, build docs in additional formats
-formats: all
-
-python:
-  install:
-    - requirements: ./docs/requirements.txt