migration from EDProducer to stream::EDProducer (SeedGeneratorFromProtoTracksEDProducer)

as reported by @fwyzard 
https://docs.google.com/spreadsheets/d/1D9khDvOl05WEbznsUPCusEbrHeep9hh8cXedMXX09Gc/edit#gid=0
there are modules used @HLT which still need to be migrated and be multithread safe

this is my first update
hope everything is fine

moreover, could you confirm me that it is not needed to back-port neither in 73x nor in 72x ?
thanks