auth: Add a page to setup web client ID for a service.

appengine/components/components/auth/ui/templates/bootstrap_done.html

Index: appengine/components/components/auth/ui/templates/bootstrap_done.html
diff --git a/appengine/components/components/auth/ui/templates/bootstrap_done.html b/appengine/components/components/auth/ui/templates/bootstrap_done.html
index 7c840ab8169d81e0fd40a7176a540f29aad7f820..f6fcda43ff05870d4280c5ce25e6771909290630 100644
--- a/appengine/components/components/auth/ui/templates/bootstrap_done.html
+++ b/appengine/components/components/auth/ui/templates/bootstrap_done.html
@@ -5,11 +5,16 @@
 <h2>You've been added to {{admin_group}} group.</h2>
 <p>Once this change propagates (~1 min) you should be able to access
 <a href="/auth">Auth Admin UI</a> and other protected pages.</p>
+<p>Meanwhile, you can configure OAuth2 client ID used by the web UI by visiting
+<a href="/auth/bootstrap/oauth">OAuth client ID configuration</a> page.</p>
 {% else %}
 <h2>You are already a member of {{admin_group}} group.</h2>
 <p>You should be able to access <a href="/auth">Auth Admin UI</a> and other
 protected pages. It takes up to 1 min for recent changes to propagate, be
 patient.</p>
+<p>If you are looking for how to configure OAuth2 client ID used by the web UI,
+visit <a href="/auth/bootstrap/oauth">OAuth client ID configuration</a> page.
+</p>
 {% endif %}
 {% if return_url %}
 <p>Go back to <a href="{{return_url}}">{{return_url}}</a>.</p>