Use tagged docker images in templates

When a release is created, the deploy.sh script should be "locked" to use the right version for docker images and not the latest one.
So, we have to:

1. add docker image tag variable to deployment.properties with value latest
2. change web-template.json and web-template-empty-dir-executor.json to reference images docker.io/windup3/windup-web-openshift with tag value from the above property
3. change release_windup_web.sh to have a further sed command to change docker image tag variable value in deployment.properties from latest to $REL
4. create a build/release_windup_openshift.sh script to build the images and push them to docker registry with the $REL tag
5. update release check list to include windup-openshift project