Update site footer and add link to Support page on Bazel site.

Issue: bazelbuild/bazel#19

_includes/footer-content.html

@@ -0,0 +1,38 @@
+<div class="container">
+  <div class="row">
+    <div class="col-md-4">
+      <p>About</p>
+      <ul class="list-unstyled">
+        <li><a href="https://github.com/bazelbuild/bazel/wiki/Bazel-Users">Who's using Bazel</a></li>
+        <li><a href="{{ site.main_site_url }}/support.html">Get Support</a></li>
+        <li><a href="{{ site.main_site_url }}/roadmap.html">Roadmap</a></li>
+        <li><a href="{{ site.main_site_url }}/contributing.html">Contribute</a></li>
+        <li><a href="{{ site.main_site_url }}/governance.html">Governance Plan</a></li>
+      </ul>
+    </div>
+    <div class="col-md-4">
+      <p>Support</p>
+      <ul class="list-unstyled">
+        <li><a href="http://stackoverflow.com/questions/tagged/bazel">Stack Overflow</a></li>
+        <li><a href="https://github.com/bazelbuild/bazel/issues">Issue Tracker</a></li>
+        <li><a href="https://docs.bazel.build">Documentation</a></li>
+        <li><a href="{{ site.main_site_url }}/faq.html">FAQ</a></li>
+        <li><a href="https://docs.bazel.build/support.html">Support Policy</a></li>
+      </ul>
+    </div>
+    <div class="col-md-4">
+      <p>Stay Connected</p>
+      <ul class="list-unstyled">
+        <li><a href="https://twitter.com/bazelbuild">Twitter</a></li>
+        <li><a href="https://blog.bazel.build">Blog</a></li>
+        <li><a href="https://github.com/bazelbuild/bazel">GitHub</a></li>
+        <li><a href="https://groups.google.com/forum/#!forum/bazel-discuss">Discussion group</a></li>
+      </ul>
+    </div>
+  </div>
+  <div class="row">
+    <div class="col-lg-12">
+      <p class="text-muted">&copy; {{ 'now' | date: "%Y" }} Google</p>
+    </div>
+  </div>
+</div>

_includes/footer.html

@@ -1,31 +1,5 @@
     <footer class="footer">
-      <div class="container">
-        <div class="row">
-          <div class="col-md-6">
-            <p>Stay Connected</p>
-            <ul class="list-unstyled">
-              <li><a href="https://twitter.com/bazelbuild">Twitter</a></li>
-              <li><a href="https://blog.bazel.build">Blog</a></li>
-              <li><a href="https://github.com/bazelbuild/bazel">GitHub</a></li>
-              <li><a href="https://groups.google.com/forum/#!forum/bazel-discuss">User mailing list</a></li>
-            </ul>
-          </div>
-          <div class="col-md-6">
-            <p>Support</p>
-            <ul class="list-unstyled">
-              <li><a href="http://stackoverflow.com/questions/tagged/bazel">StackOverflow</a></li>
-              <li><a href="https://github.com/bazelbuild/bazel/issues">Issue Tracker</a></li>
-              <li><a href="https://docs.bazel.build">Documentation</a></li>
-              <li><a href="/faq.html">FAQ</a></li>
-            </ul>
-          </div>
-        </div>
-        <div class="row">
-          <div class="col-lg-12">
-            <p class="text-muted">&copy; {{ 'now' | date: "%Y" }} Google</p>
-          </div>
-        </div>
-      </div>
+      {% include footer-content.html %}
     </footer>
 
     <!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->