All clones in a Jenkins build should support ssh protocol with credentials

[AdamBrousseau]

1. Cloning the OpenJ9 extensions repo. This is a blocker for me.

• There is a flag in configureBuild.sh that will swap the url but it proceeds assuming there is an ssh key on the machine. The pipeline groovy should wrap that step in an ssh-agent if a cred is supplied.

2. Cloning ci-jenkins-pipelines repo
3. Cloning openjdk-build repo
4. Get OpenJ9 sources? Might come for free with #1

[M-Davies]

This is in place for the job generation but I'm unsure if that applies to ssh protocol or not. I assume we would need to add/alter the repositories map in the defaults.json to understand ssh url's if this is not the case

[AdamBrousseau]

Also realized I would only be able to dump the private keys on machines as a temp workaround. So I would still be stuck for docker based compiles, unless the ssh dir is visible/mounted to the container which I don't believe it is.