Update header.html with current nav links

source/_templates/partials/header.html

@@ -1,18 +1,16 @@
 <header role="banner" class="main-header" id="main-header">
   <h1 class="main-header__logo">
-    <a href="https://kobotoolbox.org/#home">KoboToolbox</a>
+    <a href="https://www.kobotoolbox.org/">KoboToolbox</a>
   </h1>
   <nav class="main-header__navigation" role="navigation">
     <ul>
-      <li><a href="https://kobotoolbox.org/#home">Home</a></li>
-      <li><a href="https://kobotoolbox.org/#features">Features</a></li>
-      <li><a href="https://kobotoolbox.org/#sign-up">Sign Up</a></li>
-      <li><a href="https://kobotoolbox.org/#about">About</a></li>
-      <!--
-        NOTE: on kobotoolbox.org HELP scroll-navigates to a lower section, but
-        here we use this link as a support home page url
-      -->
-      <li class="current"><a href="{{ pathto(master_doc) }}">Help</a></li>
+      <li><a href="https://www.kobotoolbox.org/">Home</a></li>
+      <li><a href="https://www.kobotoolbox.org/about-us">About us</a></li>
+      <li><a href="https://www.kobotoolbox.org/features">Features</a></li>
+      <li><a href="https://www.kobotoolbox.org/services">Services</a></li>
+      <li><a href="https://www.kobotoolbox.org/how-it-works">How it works</a></li>
+      <li><a href="https://www.kobotoolbox.org/blog">Blog</a></li>
+      <li class="current"><a href="https://www.kobotoolbox.org/help">Help</a></li>
       <li>
         <a class="button" href="https://kobotoolbox.org/donate">Donate</a>
       </li>