Add Azure and Google Cloud CLIs to tests Dockerfile.
Add Jenkinsfile for Azure testing job. This job requires the following:
- Jenkins secret file for Azure credentials in JSON (AZURE_CREDENTIALS param)
- Two additional secrets for SSH public and private keys used when creating
the VMs (SSH_PRIVATE_KEY, SSH_PUBLIC_KEY)

Change-Id: Id4a0a1f401bc6a917532dd7498b187bf5887ea76
Signed-off-by: aguilard <e.dah.tid@telefonica.com>