.github: add deployment and test workflows

Taken from https://docusaurus.io/docs/deployment#deploying-to-github-pages

.github/workflows/deploy.yml

@@ -0,0 +1,43 @@
+name: Deploy to GitHub Pages
+
+on:
+  push:
+    branches:
+      - main
+    # Review gh actions docs if you want to further define triggers, paths, etc
+    # https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#on
+
+permissions:
+  contents: write
+
+jobs:
+  deploy:
+    name: Deploy to GitHub Pages
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+        with:
+          node-version: 18
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+      - name: Build website
+        run: npm run build
+
+      # Popular action to deploy to GitHub Pages:
+      # Docs: https://github.com/peaceiris/actions-gh-pages#%EF%B8%8F-docusaurus
+      - name: Deploy to GitHub Pages
+        uses: peaceiris/actions-gh-pages@v3
+        with:
+          github_token: ${{ secrets.GITHUB_TOKEN }}
+          # Build output to publish to the `gh-pages` branch:
+          publish_dir: ./build
+          # The following lines assign commit authorship to the official
+          # GH-Actions bot for deploys to `gh-pages` branch:
+          # https://github.com/actions/checkout/issues/13#issuecomment-724415212
+          # The GH actions bot is used by default if you didn't specify the two fields.
+          # You can swap them out with your own user credentials.
+          user_name: github-actions[bot]
+          user_email: 41898282+github-actions[bot]@users.noreply.github.com

.github/workflows/test-deploy.yml

@@ -0,0 +1,24 @@
+name: Test deployment
+
+on:
+  pull_request:
+    branches:
+      - main
+    # Review gh actions docs if you want to further define triggers, paths, etc
+    # https://docs.github.com/en/actions/using-workflows/workflow-syntax-for-github-actions#on
+
+jobs:
+  test-deploy:
+    name: Test deployment
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v3
+      - uses: actions/setup-node@v3
+        with:
+          node-version: 18
+          cache: yarn
+
+      - name: Install dependencies
+        run: yarn install --frozen-lockfile
+      - name: Test build website
+        run: yarn build