CloudBridge-Demo-Loop example + Connectivity test

[almahmoud]

The script at: https://github.com/almahmoud/cloudbridge-demo-loop has evolved and become a pretty solid way to boot up instances in bulk with cloudbridge. I thought it'd be good to add it as a concrete example of how CloudBridge can be used across providers + integrate it with tests as a connectivity test given that it SSHs into the created machine.