- Removes the hard-coded magic number of 60 seconds allowing users to
choose the period that they require.
- Standardise on strings for DictOpt dict keys. When loaded from a config
file, the DictOpt keys are parsed as strings, which was conflicting with
the default integer dict keys. This caused the periodic engine to silently
fail to load when configured via a config file.
- Remove unused variable
Story: 2006783
Task: 37313
Change-Id: Ibd61c45fc1ade37022150d34a5b00c56fdf69814