packaging: add Docker file for Android

* based on Ubuntu 15.10
* installs Java 8, Android SDK, Android NDK, Gradle

Tuleap: #126
Change-Id: Ib4c33ca72673b07b395a77974e2e36f419b24e81

docker/android/Dockerfile

+FROM ubuntu:15.10
+
+# Never ask for confirmations
+ENV DEBIAN_FRONTEND noninteractive
+RUN echo "debconf shared/accepted-oracle-license-v1-1 select true" | debconf-set-selections
+RUN echo "debconf shared/accepted-oracle-license-v1-1 seen true" | debconf-set-selections
+
+RUN apt-get update && ( apt-get upgrade -y || apt-get upgrade -y || apt-get upgrade -y )
+RUN apt-get install -y software-properties-common python-software-properties bzip2 unzip openssh-client git lib32stdc++6 lib32z1 --fix-missing
+
+# Add oracle-jdk7 to repositories
+RUN add-apt-repository ppa:webupd8team/java
+
+# Install oracle-jdk8
+RUN apt-get update
+RUN apt-get -y install oracle-java8-installer oracle-java8-set-default
+
+RUN wget http://dl.google.com/android/android-sdk_r24-linux.tgz
+RUN tar -xvzf android-sdk_r24-linux.tgz
+RUN mv android-sdk-linux /usr/local/android-sdk
+RUN rm android-sdk_r24-linux.tgz
+
+# Install Android tools
+RUN ( sleep 5 && while [ 1 ]; do sleep 1; echo y; done ) | /usr/local/android-sdk/tools/android update sdk --filter tool,platform-tool,platform-23,android-23,extra,addon-google_apis-google-23,addon-google_apis_x86-google-23,build-tools-23.1.0 --no-ui -a
+
+# Install Android NDK
+RUN wget http://dl.google.com/android/ndk/android-ndk-r10e-linux-x86_64.bin
+RUN chmod a+x android-ndk-r10e-linux-x86_64.bin
+RUN ./android-ndk-r10e-linux-x86_64.bin
+RUN mv android-ndk-r10e /usr/local/android-ndk
+RUN rm android-ndk-r10e-linux-x86_64.bin
+
+# Install Gradle
+RUN wget https://downloads.gradle.org/distributions/gradle-2.8-bin.zip
+RUN unzip gradle-2.8-bin.zip
+RUN mv gradle-2.8 /usr/local/gradle
+RUN rm gradle-2.8-bin.zip
+
+# Environment variables
+ENV ANDROID_HOME /usr/local/android-sdk
+ENV ANDROID_SDK_HOME $ANDROID_HOME
+ENV ANDROID_NDK_HOME /usr/local/android-ndk
+ENV GRADLE_HOME /usr/local/gradle
+ENV PATH $PATH:$ANDROID_SDK_HOME/tools
+ENV PATH $PATH:$ANDROID_SDK_HOME/platform-tools
+ENV PATH $PATH:$ANDROID_NDK_HOME
+ENV PATH $PATH:$GRADLE_HOME/bin
+
+# Export JAVA_HOME variable
+ENV JAVA_HOME /usr/lib/jvm/java-8-oracle