Administrative VMs / containers for provider services

Create a standard way of defining administrative vms / containers. These are vms that can plug into a project network (or management network) but are managed by the provider instead of the end user.

Currently we have one type of administrative VM that is handled through custom code paths (pipelib.py) . VMs of this nature are very useful for providing various cloud services such as load balancing, queuing systems, databases, load balancers, network bridging components, etc. We need a consistent way to define these administrative vms, as well as apis for controlling them. This common definition should support both containers and traditional vms, perhaps even colocated on the same infrastructure.