Add distributed timer gateway

[offbynull]

A timer is local to the sever it's running on. The problem is that this ends up binding an actor to that server. Because the timer triggers are happening on that server, the actor will always be pulled down to that server.

A new distributed timer implementation can be built based off of the checkpoint queues in Redis and JDBC. This will ensure an even spread of actor executions across a server cluster.

[offbynull]

Might not actually be true, as the timer just places a message into the actor's message queue once it hits.