[TACHYON-62] Netty

Netty implementation of the data server.

This patch is not done yet.  Its intent is to show the work I have right now for commenting.

This PR should not be merged until performance results come in.
Rather keep it separate.  It tries to not distract the reader of `setupGroups` with the details on how its generate.

Also, I will most likely need to split the groups into two thread pools when I add the write path, so this will be called twice then.