Build sdist inside of a container

A lot of people have experienced issues with the system-level dependencies that are required in order to build the source distribution that is handed off to the image builds. This makes it unnecessary to install any additional software on the host machine aside from Ansible and Docker.

installer/image_build/files/Dockerfile.sdist

@@ -0,0 +1,20 @@
+FROM centos:7
+
+RUN yum install -y epel-release
+
+RUN yum install -y bzip2 \
+    gcc-c++ \
+    gettext \
+    git \
+    make \
+    python \
+    python-pip
+
+RUN curl --silent --location https://rpm.nodesource.com/setup_6.x | bash -
+RUN yum install -y nodejs
+RUN npm set progress=false
+
+WORKDIR "/awx"
+
+ENTRYPOINT ["/bin/bash", "-c"]
+CMD ["make sdist"]