优化default和serverstatus主题模版 (#327)

1.优化default主题模版
2.优化serverstatus主题模版

resource/template/theme-default/footer.html

@@ -0,0 +1,12 @@
+{{define "theme-default/footer"}}
+</div>
+<div class="ui inverted vertical footer segment">
+    <div class="ui center aligned is-size-7 container">
+        <b>&copy; <a style="color: white;" href="/">{{.Conf.Site.Brand}}</a></b> | <small>Powered by <a
+                href="https://github.com/naiba/nezha" style="color: white;" target="_blank">{{tr "NezhaMonitoring"}}</a>
+            {{.Version}}</small>
+    </div>
+</div>
+</body>
+</html>
+{{end}}