Add etcd defragmentation service + timer.
Created by: garloff
Unconditionally apply heartbeat/election timing tweaks. Unnice/IO-unnice etcd. Wait for etcd to have restarted before doing it.
More importantly: Add nightly etcd-defrag job. (#279) Heavily inspired by Sven Batista Steinbach from syself' work on the Cluster-API based Cluster Management for Hetzner.
Signed-off-by: Kurt Garloff kurt@garloff.de