Construct Job image

[bronhaim]

Currently base image for fencing job is construct from by dockerfile:

FROM centos:7
RUN yum upgrade -y;
RUN yum install fence-agents-all -y; yum clean all                              
ADD fencing-scripts/* /usr/sbin   

This base image should include all fencing scripts and should be the base image also for the controller - the controller needs to read dynamically the meta-data from each fence script that we have in the job image.