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.
# Add project specific ProGuard rules here.
# By default, the flags in this file are appended to flags specified
# in /opt/android-sdk-update-manager/tools/proguard/proguard-android.txt
# You can edit the include path and order by changing the proguardFiles
# directive in build.gradle.
#
# For more details, see
# http://developer.android.com/guide/developing/tools/proguard.html
# Add any project specific keep options here:
# If your project uses WebView with JS, uncomment the following
# and specify the fully qualified class name to the JavaScript interface
# class:
#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
# public *;
#}