Support configurable settings for various async sleep times.

[robertbartel]

There are several spots in our async service logic where we call sleep(), typically at the end of a looping periodic task to wait before running it again. These usages should be examined and, where appropriate, support for controlling the specific amount of time should be added via either externalized configuration or parameterization.

A particular example is in python/services/monitorservice/dmod/monitorservice/service.py within the exec_monitoring() function.