feat(WEB-93): add Header to CMS and render it in Next

components/Current/Header/OfflineBanner/index.tsx

@@ -0,0 +1,10 @@
+import styles from "./banner.module.css"
+
+export default function OfflineBanner() {
+  return (
+    <div className={`${styles.banner} ${styles.hidden}`}>
+      You are offline, some content may be out of date.
+      <button className={styles.reloadBtn} type="button">Reload</button>
+    </div>
+  )
+}