Description

ILM will wait for conditions to be fulfilled before making progress.
E.g. it waits for indices to be GREEN in the wait-for-active-shards step

It'd be useful for the health API to signal if ILM is not making progress.
We could derive a configurable heuristic based on the time ILM entered a step,
available in the ILM execution state (and visible via the explain API under step_time) and
signal a YELLOW status if ILM is idling in a wait-* step for more than 24 (or 48?) hours.