Add BlockingHandler to simplify running blocking operations

We have quite a few places that must run blocking operations that cannot be changed. These places must run the operation in a blocking thread and return on a non blocking thread. All of these places must register both a blocking and non blocking thread pool and properly handle them. This is both error prone and a lot of extra code. We should isolate this to a shared component which will in turn provide for an easier way to find such operations.