feat(*): enable snapshots by default

Ben recently added test coverage for snapshots so we should enable it in
etcd. Lets do this.

https://github.com/goraft/raft/commit/1d66f6a111793e66877d4ce8427c2e2e6b9e29df
feat(server): log on snapshot success or failure

lila.local: snapshot of 12 events completed at index 479
lila.local: snapshot of 12 events at index 491 attempted and failed: handling snapshot
Merge pull request #507 from philips/turn-snapshots-on-by-default

feat(*): enable snapshots by default