ws-manager: Add volume snapshot related events to workspace pod event log

[sagor999]

It would be great if we could add events to workspace pod that show the progress of volume snapshot operations: kubectl describe pods
That way it will be easier to debug later on if workspace pod is stuck or misbehaving.

Thanks @aledbf for an idea!

Related to epic: #7901

[sagor999]

@jenting would like to look into this one? (not a high priority)

[jenting]

Sure