vagrant: add support for Android SDK

Created by: derkling

1. Install the android SDK (android-sdk_r24.4.1-linux.tgz cmdline tool - upgrade after the installation for the platform-tools) in the same share area where vagrant is sharing the host fs folder.
2. define ANDROID_HOME (I added the platform-tools to the PATH also) in the bash.bashrc of the VM instance created

For the first point I would suggest to install the Android SDK on the same lisa source tree, which is mounted under /vagrant. We have a lisa/tools folder, we can unzip the SDK in there so that it is available for all the VM and/or container we want to use starting from the LISA source tree. The Vagrant provisioning script thus has to check before if the SDK is already available, otherwise download and install it under /vagrant/tools/android-sdk. This is the path used for the ANDROID_HOME.