[vpp-dev] worker_thread creation #vpp

[mbly]

Looking to confirm worker_thread creation/deletion capabilities. 
./src/vpp/conf/startup.conf descriptions suggest we must define the number of 
worker_threads up front. I am looking to understand if that is correct, or if 
we can add/remove worker_threads from a live system over time as workloads come 
and go.
-MikeB