ISPN-4867 Single event marshaller support more clearly defined in API

* Based on Dan's feedback, Hot Rod server API made it look as if you
could pass a per-factory marshaller but that's not really the case.
A single event marshaller is currently supported.
ISPN-4675 Missing server configuration for remote executor thread pool

Add server configuration for the remote command executor and the total order executor.
ISPN-4828 Increasing default internal thread pool size

* Use the JGroups defaults for the internal thread pool (core = 2, max = 4)
* Increase the max size of the remote executor thread pool to 200 (core = 1)