Threaded bulk insert (#1596)

* Update the bulk updater to execute on a thread

* Bulk loader endpoint locks for minimal time

* TODOs

* Use a separate thread pool for bulk operations

* Update test_thread_pools.cpp

* refactor bulk-insert

* Fix PR problems

* count number of pings during bulk-insert, only create graph context on BEGIN token

Co-authored-by: swilly22 <[email protected]>
Co-authored-by: Roi Lipman <[email protected]>

Author: jeffreylovitz

.astylerc

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