Moved Command into Actions, since it is not really part of the definition of a Log. Also, rearranged some imports, and re-exported some modules from Raft.
More consolidation of imports / exports, so that only 1 import will generally be needed (Control.Consensus.Raft).
Simplification by removing the Command type class. Can't do quite the same amount of logging internal to the algorithm, but types are tighter.