Added base template for config ui.

appengine/config_service/ui/src/config-ui/config-ui.html

+<!--
+  Copyright 2017 The LUCI Authors. All rights reserved.
+  Use of this source code is governed under the Apache License, Version 2.0
+  that can be found in the LICENSE file.
+-->
+
+<link rel="import" href="../../bower_components/polymer/polymer.html">
+<link rel="import" href="../../bower_components/app-layout/app-layout.html">
+<link rel="import" href="../../bower_components/paper-search/paper-search-bar.html">
+
+<dom-module id="config-ui">
+  <template>
+    <style>
+      html, body {
+        margin: 0;
+        background: #f1f1f1;
+      }

[turakulov, 2017/06/08 01:22:00]

Why this style is defined in this file as opposed to index.html?
The html and body tags are defined there, not here

+
+      app-toolbar {
+        background-color: #efefef;
+        color: #232323;
+      }
+
+      app-header {
+        @apply --layout-fixed-top;
+      }
+
+      .title {
+        padding-left: 1%;
+        padding-bottom: 0.5%;
+        font-size: 150%;
+        font-family: sans-serif;
+      }
+
+      .search {
+        padding-top: 15%;
+      }
+
+      paper-search-bar {
+        border-style: solid;
+        border-width: 2px;
+        width: 40%;
+        margin: auto;
+      }
+    </style>
+    <app-header reveals>
+      <app-toolbar>
+        <image src="../../images/google.png"/>

[turakulov, 2017/06/08 01:22:00]

Is this a Google logo? I am not sure branding team would approve this. Better to
use Chromium logo

+        <div class="title" main-title>Configuration Service</div>
+      </app-toolbar>
+    </app-header>
+
+    <center class="search">
+      <paper-search-bar><paper-search-bar>
+    </center>
+  </template>
+
+  <script>
+    Polymer({
+      is: 'config-ui'
+    });
+  </script>
+</dom-module>