Split centraldogma-server module

[minwoox]

This idea was suggested by @ikhoon.

The centraldogma-testing module depends on the centradogma-server module which has ZooKeeper dependency. However, users don't need the replication feature for Central Dogma server and sometimes the ZooKeeper dependency causes a dependency conflict with other libraries.

So it would be nice to split centraldogma-server module into two, one that has a replication feature and one that doesn't have it.

- centraldogma-server
  - centraldogma-server-standalone
  - centraldogma-server-replication
- centraldogma-testing
  - centraldogma-server-standalone