Host Maintenance API v1
These APIs are meant for infrastructure admin who is in charge of triggering the rolling maintenance and upgrade workflows.
These APIs are meant for projects having instances on top of the infrastructure under corresponding rolling maintenance or upgrade session. Usage of these APIs expects there is an application manager (VNFM) that can interact with Fenix workflow via these APIs. If this is not the case, workflow should have a default behavior for instances owned by projects, that are not interacting with Fenix.