web: Add a workflow for Github Pages

The manual is now built automatically with each
push to the master branch.

Author: zacikpa

.github/workflows/pages.yml

@@ -0,0 +1,50 @@
+name: Deploy TuneD website to Pages
+
+on:
+  push:
+    branches:
+      - master
+
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout the master branch
+        uses: actions/checkout@v4
+      - name: Install dependencies
+        run: |
+          sudo apt install -y make asciidoctor
+      - name: Build the manual
+        run: make -C doc/manual
+      - name: Prepare the website contents
+        run: |
+          git fetch origin gh-pages:gh-pages
+          git clone -b gh-pages . _site
+          cp doc/manual/index.html _site/docs/manual.html
+      - name: Setup Pages
+        id: pages
+        uses: actions/configure-pages@v5
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    needs: build
+    steps:
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4