Link to an existing account: split in two steps

There is now two steps when linking to an existing accounts. The first
page explains to the user how to generate the PIN on the other device.

Tuleap: #1296
Change-Id: If3fb24f0a5b2d7e733a2cc3d5640ff81997d1d5b
diff --git a/ui/accountcreationwizard.ui b/ui/accountcreationwizard.ui
index ebf94e1..bd2481e 100644
--- a/ui/accountcreationwizard.ui
+++ b/ui/accountcreationwizard.ui
@@ -89,15 +89,79 @@
               </object>
             </child>
             <!-- End Choose account type wizard -->
-            <!-- Existing account wizard -->
+            <!-- Existing account wizard: step 1 -->
             <child>
-              <object class="GtkBox" id="existing_account">
+              <object class="GtkBox" id="existing_account_step1">
                 <property name="visible">True</property>
                 <property name="valign">center</property>
                 <property name="border_width">10</property>
                 <property name="orientation">vertical</property>
                 <property name="spacing">15</property>
                 <child>
+                  <object class="GtkLabel">
+                    <property name="visible">True</property>
+                    <property name="can_focus">False</property>
+                    <property name="label" translatable="yes">Link this device to an existing account</property>
+                    <attributes>
+                      <attribute name="weight" value="bold"/>
+                    </attributes>
+                  </object>
+                </child>
+                <child>
+                  <object class="GtkLabel">
+                    <property name="visible">True</property>
+                    <property name="valign">center</property>
+                    <property name="halign">center</property>
+                    <property name="max-width-chars">80</property>
+                    <property name="can_focus">True</property>
+                    <property name="wrap">True</property>
+                    <property name="justify">left</property>
+                    <property name="label" translatable="yes">To link this device to another account, you first need to obtain a PIN code. To generate the pin code, go to the account management setting of a previous device, choose the Ring Account to use and select "Link another device to this account". You will get the necessary PIN to complete this form. The PIN is only valid for 10 minutes.</property>
+                  </object>
+                </child>
+                <child>
+                  <object class="GtkButtonBox">
+                    <property name="visible">True</property>
+                    <child>
+                      <object class="GtkButton" id="button_existing_account_step1_previous">
+                        <property name="label" translatable="yes">Previous</property>
+                        <property name="visible">True</property>
+                        <property name="can_focus">True</property>
+                        <property name="halign">start</property>
+                      </object>
+                    </child>
+                    <child>
+                      <object class="GtkButton" id="button_existing_account_step1_next">
+                        <property name="label" translatable="yes">Okay, I have the PIN!</property>
+                        <property name="visible">True</property>
+                        <property name="can_focus">True</property>
+                        <property name="halign">end</property>
+                      </object>
+                    </child>
+                  </object>
+                </child>
+              </object>
+            </child>
+            <!-- End of Existing accoutn wizard: step2 -->
+            <!-- Existing account wizard: step 2 -->
+            <child>
+              <object class="GtkBox" id="existing_account_step2">
+                <property name="visible">True</property>
+                <property name="valign">center</property>
+                <property name="border_width">10</property>
+                <property name="orientation">vertical</property>
+                <property name="spacing">15</property>
+                <child>
+                  <object class="GtkLabel">
+                    <property name="visible">True</property>
+                    <property name="can_focus">False</property>
+                    <property name="label" translatable="yes">Link this device to an existing account</property>
+                    <attributes>
+                      <attribute name="weight" value="bold"/>
+                    </attributes>
+                  </object>
+                </child>
+                <child>
                   <object class="GtkBox" id="vbox_existing_account_entry">
                     <property name="visible">True</property>
                     <property name="valign">center</property>
@@ -148,7 +212,7 @@
                   <object class="GtkButtonBox">
                     <property name="visible">True</property>
                     <child>
-                      <object class="GtkButton" id="button_existing_account_previous">
+                      <object class="GtkButton" id="button_existing_account_step2_previous">
                         <property name="label" translatable="yes">Previous</property>
                         <property name="visible">True</property>
                         <property name="can_focus">True</property>
@@ -156,7 +220,7 @@
                       </object>
                     </child>
                     <child>
-                      <object class="GtkButton" id="button_existing_account_next">
+                      <object class="GtkButton" id="button_existing_account_step2_next">
                         <property name="label" translatable="yes">Next</property>
                         <property name="visible">True</property>
                         <property name="sensitive">False</property>
@@ -168,7 +232,7 @@
                 </child>
               </object>
             </child>
-            <!-- End existing account wizard -->
+            <!-- End existing account wizard: step 2 -->
             <!-- account creation wizard -->
             <child>
               <object class="GtkBox" id="account_creation">