A plugin enabled implementation of DiagnoseTargets
Summarized Changes:
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* move argument collection into Thresholder object
* make thresholder object private member of all statistics classes
* rework the logic of the mate pairing thresholds
* update unit and integration tests to reflect the new behavior
* Implements Locus Statistic plugins
* Extend Locus Statistic plugins to determine sample status
* Export all common plugin functionality into utility class
* Update tests accordingly
[fixes#48465557]
fdd16dc6f9