Ability for users to do indexer health check

There needs to be a simplified mechanism for users to do indexer health check in addition to the UI stats. 

Right now some of the problems are very hard to diagnose and may lead to longer downtime for customers e.g.

1. If any of the indexer->projector request gets stuck, customers/support find it very difficult to figure that out and take corrective action.
2. "High Items Remaining" - It is difficult to identify what part of the pipeline is the bottleneck (projector, indexer, storage).
3. Projector hangs - There is no way to tell this.
4. Indexer stuck during warmup - All the indexes related to the indexer go off the UI. It is hard for users to tell what is going on.
5. Indexer warmup progress - If indexer crashes and restarts, it may take some time to come back up. Users have no way to figure out what is going on.

Some of these should definitely be made available as part of the UI.