Android: add Dockerfile for build environment

We'll use that on Travis, but anyone can use that on their system.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

scripts/docker/android-build-container/Dockerfile

@@ -0,0 +1,32 @@
+From ubuntu:18.04
+
+RUN apt-get update  && \
+    apt-get upgrade -y && \
+    apt-get install -y \
+    autoconf \
+    automake \
+    git \
+    libtool-bin \
+    make \
+    cmake \
+    wget \
+    unzip \
+    python \
+    bzip2 \
+    pkg-config \
+    libx11-xcb1 \
+    libgl1-mesa-glx \
+    libglib2.0-0 \
+    openjdk-8-jdk
+
+RUN mkdir -p /android
+ADD qt-opensource-linux-x64-5.11.1.run /android/
+ADD android-ndk-r14b-linux-x86_64.zip /android/
+ADD android-build-wrapper.sh variables.sh qt-installer-noninteractive.qs /android/
+
+RUN cd /android && bash -x /android/android-build-wrapper.sh -prep-only && \
+    rm -f qt-opensource-linux-x64-5.11.1.run android-ndk-r14b-linux-x86_64.zip && \
+    rm -rf android-sdk-linux/emulator Qt/Docs Qt/Tools  Qt/Examples && \
+    rm -rf $( find android-ndk*/platforms -name arch-mips -o -name arch-x86 ) && \
+    ls -l && \
+    du -sh *