docs: Add Doxygen and project-related documentation

.github/workflows/doxygen.yaml

@@ -0,0 +1,40 @@
+name: doxygen
+run-name: Generate and deploy Doxygen documentation
+on: 
+  push:
+    branches:
+      - "master"
+  workflow_dispatch: {}
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+        uses: actions/configure-pages@v3
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.9'
+          cache: 'pip' # caching pip dependencies
+      - run: pip install doxyqml
+      - name: Doxygen
+        uses: uses: mattnotmitt/[email protected]
+      - name: Upload GitHub pages artifact
+        uses: "actions/upload-pages-artifact@v2"
+        with:
+          path: "doxygen/html/"
+
+  deploy:
+    runs-on: ubuntu-latest
+    needs: build
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: "actions/deploy-pages@v2"

.gitignore

@@ -5,6 +5,7 @@ rpm/*.spec
 build/
 build-*/
 .dub/
+doxygen/
 
 # IDE files
 *.user

.gitmodules

@@ -0,0 +1,6 @@
+[submodule "core/doc/doxygen-awesome-css"]
+	path = core/doc/doxygen-awesome-css
+	url = https://github.com/jothepro/doxygen-awesome-css.git
+[submodule "3rdparty/doxygen-awesome-css"]
+	path = 3rdparty/doxygen-awesome-css
+	url = https://github.com/jothepro/doxygen-awesome-css.git