The anti-entropy code manages background synchronizations of the local
state on a regular basis or on demand when either the state has changed
or a new consul server has been added.
This patch moves the anti-entropy code into its own package and
decouples it from the local state code since they are performing
two different functions.
To simplify code-review this revision does not make any optimizations,
renames or refactorings. This will happen in subsequent commits.
Frank Schroeder