refactor fabric8 release workflow scripts to be reusable and automate CD pipeline

[rawlingsj]

Currently the groovy scripts duplicate a lot of code, we should instead leverage the global workflow library and create reusable functions for releasing projects.

• For end to end automation we should also raise pull requests when updating released dependencies so that the CI tools can catch any merge conflicts which need resolving.
• We should tag latest fabric8 docker images
• Include human approval
• Alerts and notification with hubot / slack
• Run the system test before releasing ipaas, devops and quickstart to maven central

[rawlingsj]

this has been done now. release uses functions from the jenkins global library