There is a problematic scenario with x-pack-cluster master-nodes
attempting to install custom metadata into the cluster-state and
broadcasting that to non-x-pack-enabled nodes. Since those nodes
are not aware of this custom metadata, their cluster-state recovery
will be broken. This change ensures that newly-elected x-pack master
nodes bootstrap IndexLifecycleMetadata upon the first request to
leverage its features. This means that PutLifecycleAction is
now responsible for installing the metadata. Since this X-Pack API
can only be called once all nodes in the cluster have x-pack enabled,
it is safe to assume that the cluster will appropriately handle the
cluster-state recovery with the new set of index-lifecycle metadata.