docs: migrate to MkDocs for site generation (#5227)

.github/workflows/site-pr.yml

@@ -0,0 +1,22 @@
+name: Build Site Image
+
+on:
+  pull_request:
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v3
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@v2
+
+      - name: Build
+        uses: docker/build-push-action@v4
+        with:
+          context: .
+          file: ./Dockerfile.site
+          push: false
+