Interface for Recovery manager plug-in module.
RecoveryModules are registered via the properties mechanisms.
The periodicWorkFirstPass of each module is called, then RecoveryManager
waits for the time interval RECOVERY_BACKOFF_PERIOD (seconds), then the
periodicWorkSecondPass of each module are called.
The RecoveryManager then waits for period PERIODIC_RECOVERY_PERIOD (seconds)
before starting the first pass again
The backoff period between the first and second pass is intended to allow
transactions that were in-flight during the first pass to be completed normally,
without requiring the status of each one to be checked. The recovery period
will typically be appreciably longer.