We need to debug a VM on test failures, but we do not have access to them once the build finishes, as it destroys the cloud resources.

In order to debug a VM:

1. Add the user to a list of valid users (simplest way is a text file including github username)
2. copy the users file to the ephemeral VM
3. Grant access to the user to SSH into the machine with https://github.com/dustinkirkland/ssh-import-id, which adds the public SSH key from a Github account
4. Read DEVELOPER_MODE on Jenkinsfile to not kill the VMs when it's true
5. Tag cloud VMs with e2e-testing to mark them as candidates to be removed in an automated manner and not increase the cloud bill
6. Create a reaper pipeline that runs daily/weekly removing cloud VMs tagged as e2e-testing

cc/ @adam-stokes