Provide options for several subsystems to run with consensus, e.g.

• SEQUENCER
• CENTRAL_LOCK
• COUNTER
• TOA
• Clustered singletons etc

For example, with the current impl of distributed counters (COUNTER), the same counter can be available multiple times if we have a split brain. It is currently up to the user to merge counters with different values after a split brain heals.
This is OK, but we should provide a second implementation, based on jgroups-raft, which uses consensus to determine the counter maintainer in a split brain scenario. This will forfeit availability in favor of consistency.