Move the repo cloning off the jenkins machines to the spun up vm

[yongja79]

In the websphere-liberty-operator/ebcDockerBuilderWLO.jenkinsfile we clone and stash git repos onto the jenkins machines and then copy them across to the build VMs.

It would be more efficient to move the clone down to the VMs and then not have to stash them thus speeding up builds

Would require moving the function in gitCloneAndStash(); to the doWork() function and removing all stash and unstashing function