Merge branch 'release-v1.8.6'

update changelog

update changelog

Update changelog

Update changelog

Fix: small ms solidifier fixes (#1859)

Feature: Sync check added to broadcast stage (#1856)

* Added inSyncService for use in BroadcastStage

* Changed to atomicboolean

Fix: only remove seen milestone if applied to ledger (#1855)

Fix: Use a linked blocking queue to solve network deadlock (#1833)

Put a limit on the number of transactions we walk upon in order to so…

…lidify