Add action summary and "done" message to log output.

[Will Moore]

What I'd like:
Updater currently reports successful updates as they occur. This means that larger clusters will have the results of their updates spread throughout the logs. This can make it difficult to determine if all the update attempts were successful. Additionally it is unclear from the logs if actions are still being undertaken, or if Updater is done.

As such, a summary of events should be printed to the logs at the end of its run along with a message clearly indicating that all actions are complete until the next run.

Any alternatives you've considered:
N/A