docs: Add Sphinx-based Python doc to the user doc (#5306)

Author: wenzeslaus

.github/workflows/documentation.yml

@@ -149,6 +149,14 @@ jobs:
           cd $MKDOCS_DIR
           mkdocs build
 
+      - name: Build Sphinx documentation
+        run: |
+          pip install sphinx
+          cd grass
+          make sphinxdoclib
+          ARCH="$(grass --config arch)"
+          mv -v dist.$ARCH/docs/html/libpython $MKDOCS_DIR/site
+
       - name: Make logs available
         uses: actions/upload-artifact@4cec3d8aa04e39d1a68397de0c4cd6fb9dce8ec1 # v4.6.1
         with: