multi-device: account migration

- detects a need for migration in Home screen
- offers a migration dialog in Account management screen

Tuleap: #955
Change-Id: Ia7bce09720fd0ad08a624aafde69e1be304c42ef
diff --git a/ring-android/app/src/main/res/values/strings.xml b/ring-android/app/src/main/res/values/strings.xml
index e762524..9149e88 100644
--- a/ring-android/app/src/main/res/values/strings.xml
+++ b/ring-android/app/src/main/res/values/strings.xml
@@ -166,5 +166,6 @@
     <string name="add_call_contact_number_to_contacts">Add %1$s ?</string>
     <string name="prompt_new_password">New password</string>
     <string name="prompt_new_password_repeat">Repeat new password</string>
+    <string name="account_device_updated_message">You have successfully updated your Ring account.</string>
 
 </resources>