ping-check-hook-task-6 Integrate PingCheckMgr into hook proper

Integrate PingCheckMgr into the ping-check library callouts

https://gitlab.isc.org/isc-projects/kea/-/wikis/Designs/ping-check

When complete the ping-check hook library should be fully functional, managing a PingCheckMgr singleton via hook callouts. It should unpark packets and/or decline leases when appropriate.

Depends on #3083 (closed)

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