Calls to network manager from object methods have been
moved into callbacks implemented by the network manager
extension.
This commit makes the following new callbacks available
to extensions:
* on_cluster_create: called when a new cluster is created
* on_cluster_patch_attributes: called when a cluster's attributes
are updated
* on_nodegroup_create: called when a node group is created
* on_before_deployment_serialization: called before deployment
serialization begins
* on_before_provisioning_serialization: called before provisioning
serialization begins
* on_remove_node_from_cluster: called when a node is removed from
a cluster
Blueprint: network-manager-extension
Change-Id: I9a3413f54c881edd098e623ea204d12a86695f87
76a0bc226e