Utils: Add a basic implementation of an EncryptionManager which allows to store the password encrypted.
This use the latest AndroidKeyStore from Android M and allow to store the key securely.
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
<stroke android:width="4dp" android:color="#D6F94C" />
<padding android:left="7dp" android:top="7dp"
android:right="7dp" android:bottom="7dp" />
<corners android:radius="4dp" />
</shape>