js: time module: implement utc,now,local (#11138)

vlib/time/time_js.js.v

@@ -0,0 +1,31 @@
+module time
+
+#var $timeOff = 0;
+#var $seen = 0
+#function $sys_mono_new_Date() {
+#var t = Date.now()
+#if (t < seen)
+#timeOff += (seen - t)
+#
+#seen = t
+#return t + timeOff
+#}
+
+pub fn sys_mono_now() u64 {
+	$if js_browser {
+		mut res := u64(0)
+		#res = new u64(window.performance.now() * 1000000)
+
+		return res
+	} $else $if js_node {
+		mut res := u64(0)
+		#res.val = Number($process.hrtime.bigint())
+
+		return res
+	} $else {
+		mut res := u64(0)
+		#res = new u64($sys_mono_new_Date() * 1000000)
+
+		return res
+	}
+}