chore: add 'real-dev-server-time' example

Author: Je

examples/real-dev-server-time/data.tsx

@@ -0,0 +1,7 @@
+export const refreshInterval = 1 // in seconds
+
+export default function () {
+    return {
+        'time': Date.now()
+    }
+}

examples/real-dev-server-time/pages/index.tsx

@@ -0,0 +1,15 @@
+import React, { useMemo } from 'https://esm.sh/react'
+import { useData } from 'https://deno.land/x/aleph/mod.ts'
+
+export default function Home() {
+    const time = useData('time')
+    const iso = useMemo(() => {
+        const d = new Date()
+        d.setTime(time)
+        return d.toISOString().split('.')[0].replace(/T/, ' ')
+    }, [time])
+
+    return (
+        <p>server time → <strong>{iso}</strong></p>
+    )
+}