Add initial-draft GitHub Action for Pages (#2)

From https://github.com/OwnTube-tv/web-client/actions/new?category=pages tutorial, with additional steps added for installing Node dependencies and building the React Native app.

.github/workflows/deploy-static-main.yml

@@ -0,0 +1,51 @@
+# Simple workflow for deploying static content to GitHub Pages
+name: Deploy static content to Pages
+
+on:
+  # Runs on pushes targeting the default branch
+  push:
+    branches: ["main"]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+# Sets permissions of the GITHUB_TOKEN to allow deployment to GitHub Pages
+permissions:
+  contents: read
+  pages: write
+  id-token: write
+
+# Allow only one concurrent deployment, skipping runs queued between the run in-progress and latest queued.
+# However, do NOT cancel in-progress runs as we want to allow these production deployments to complete.
+concurrency:
+  group: "pages"
+  cancel-in-progress: false
+
+jobs:
+  # Single deploy job since we're just deploying
+  deploy:
+    environment:
+      name: github-pages
+      url: ${{ steps.deployment.outputs.page_url }}
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+      - name: Setup Node 20
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20.x
+      - name: Install Dependencies
+        run: cd OwnTube.tv/ && npm install
+      - name: Build Web App
+        run: cd OwnTube.tv/ && npx expo export
+      - name: Setup Pages
+        uses: actions/configure-pages@v4
+      - name: Upload artifact
+        uses: actions/upload-pages-artifact@v3
+        with:
+          # Upload Expo build output
+          path: './OwnTube.tv/dist/'
+      - name: Deploy to GitHub Pages
+        id: deployment
+        uses: actions/deploy-pages@v4