Add submodules and configure CMake for GitHub Pages deployment

Signed-off-by: Martin Stump <11492152+globberwops@users.noreply.github.com>

.github/workflows/pages.yml

@@ -16,18 +16,26 @@ concurrency:
 jobs:
   build:
     runs-on: ubuntu-latest
+
     steps:
       - name: Install Doxygen
         run: sudo apt-get -y install doxygen graphviz
-      - name: Checkout
+
+      - name: Checkout repository
         uses: actions/checkout@v4
+        with:
+          submodules: true
+
       - name: Setup Pages
         id: pages
         uses: actions/configure-pages@v4
+
       - name: Configure with CMake
         run: cmake -B build -S ${{ github.workspace }}
+
       - name: Build with CMake
         run: cmake --build build --target gw_docs
+
       - name: Upload artifact
         uses: actions/upload-pages-artifact@v2
         with:
@@ -38,8 +46,11 @@ jobs:
     environment:
       name: github-pages
       url: ${{steps.deployment.outputs.page_url}}
+
     runs-on: ubuntu-latest
+
     needs: build
+
     steps:
       - name: Deploy to GitHub Pages
         id: deployment