add singularity test for DAQ context

base/daq-singularity

+FROM centos:7.4.1708
+  MAINTAINER Kay Graf <kay.graf@km3net.de>
+#Install Singularity as described on https://github.com/sylabs/singularity/blob/master/INSTALL.md
+  RUN	yum groupinstall -y 'Development Tools' && \
+  	yum install -y epel-release && \
+  	yum install -y golang openssl-devel libuuid-devel libseccomp-devel squashfs-tools
+  RUN yum -y update && yum install -y rpm-build wget
+  
+  RUN 	export VERSION=3.1.0 RC=-rc4 && \
+	wget https://github.com/sylabs/singularity/releases/download/v${VERSION}${RC}/singularity-${VERSION}.tar.gz && \
+	rpmbuild -tb singularity-${VERSION}.tar.gz && \
+    	rpm -ivh ~/rpmbuild/RPMS/x86_64/singularity-${VERSION}${RC}.el7.x86_64.rpm && \
+    	rm -rf ~/rpmbuild singularity-${VERSION}*.tar.gz
+
+  RUN   wget https://git.km3net.de/common/jpp/raw/master/Singularity?inline=false -O Singularity
+  RUN	singularity build Jpp.sif Singularity