Record instance actions and events

Record when an action is initiated on an instance, and the underlying
events related to completing that action.

Actions will typically occur at the API level and should match what a
user intended to do with an instance.  Events will typically track what
happens behind the scenes and may include things that would be unclear
for a user if exposed, but should be beneficial to an admin/deployer.

Adds a new wrapper to the compute manager.  The wrapper will record when
an event begins and finishes from the point of view of the compute
manager.  It will also record errors if they occur.

Blueprint instance-actions

Change-Id: I801f3e796d091e146413f84c2ccfab95ad2e1af4
API extension for accessing instance_actions

Adds a new API extension for accessing the recorded actions on an
instance.  Usage is documented with api samples.

Blueprint instance-actions

Change-Id: I1e32b492520d28eb97b4d395a6118ace38f438bc