Support protostream-based marshalling of user objects

Currently, WildFly uses JBoss Marshalling to marshal user objects (session attributes, SFSB instances) for the purposes of replication and persistence.

Protostream (developed by the Infinispan team) offers several advantages over JBoss Marshalling.

• Lower memory footprint (marshalling schemas are built during compilation time)
• Faster marshalling - as it does not rely on reflection
• Produces generally smaller replication payloads (see https://docs.google.com/spreadsheets/d/1f6FlXqxX7dYm44naHZfqLc5TjqlmscIdGyyfmt5I3f4/edit?usp=sharing )
• Resolves security concerns due to JBM's reliance on reflection and Java serialization inherently permitting arbitrary execution of rogue code
• JBoss Marshalling is effectively in maintenance mode

We can either auto-detect the intended marshaller by looking for requisite SerializationContextInitializers in the deployment classpath, and/or use an explicit configuration attribute.