* Inbound ledger and SHAMapAddNode cleanup
* Log acquire stats
* Fix progress logic
* Remove ledgers we no longer need to acquire
* Stash stale state data in our fetch pack, it can still be useful
* Stash in fetch pack if acquire terminated while job was pending
* Account for duplicate/invalid nodes in a few cases previously missed
* Dispatch each InboundLedger once (not per data)
* Trigger only the "best" peer
* Don't call tryAdvance on failed acquires