Create a periodic worker helper class

Create a simple class that can call a set of
functions periodically and use this in the case
where we run a notification thread instead of
handling this internally to the worker executor
directly.

Change-Id: I386e027cf461480799614e20e920b46788f99cab
Move the daemon thread helper function

This function seems better suited in the threading_utils module.

Change-Id: Iddd438b57973c7c6c26bd7b6239630656530bd1b
Merge "Create a periodic worker helper class"
Merge "Move the daemon thread helper function"