Initial check-in of new React docs and website

Co-authored-by: Dan Abramov <dan.abramov@me.com>
Co-authored-by: Sylwia Vargas <sylwia.vargas@gmail.com>
Co-authored-by: Dan Lebowitz <dan.lebo@me.com>
Co-authored-by: Razvan Gradinar <grazvan@fb.com>
Co-authored-by: Jared Palmer <jared@palmer.net>
Co-authored-by: Dane Grant <danecando@gmail.com>
Co-authored-by: Dustin Goodman <dustin.s.goodman@gmail.com>
Co-authored-by: Rick Hanlon <rickhanlonii@gmail.com>
Co-authored-by: Maggie Appleton <maggie.fm.appleton@gmail.com>
Co-authored-by: Alex Moldovan <alex.n.moldovan@gmail.com>
Co-authored-by: Ives van Hoorne <ives.v.h@gmail.com>
Co-authored-by: Brian Vaughn <bvaughn@fb.com>
Co-authored-by: Dmitri Pavlutin <dpavlutin@gmail.com>

.github/workflows/nodejs.yml

@@ -0,0 +1,24 @@
+name: Build
+
+on:
+  pull_request:
+    types: [opened, synchronize, reopened]
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+
+    name: Lint on node 12.x and ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v1
+      - name: Use Node.js 12.x
+        uses: actions/setup-node@v1
+        with:
+          node-version: 12.x
+
+      - name: Install deps and build (with cache)
+        uses: bahmutov/npm-install@v1
+
+      - name: Lint codebase
+        run: yarn ci-check