Rebootstrap
Also Refine:
 - Introduce MapReduceConsumeCommandStore for enforcing message refusal comprehensively
 - Refactor to RedundantStatus:
   - use int rather than short to prepare to support more statuses
   - merge PreBootstrap and Unready (into Unready)
Also Fix:
 - Propagate Erase to no longer participating replica
 - RecoverAwait to original coordinator was not correctly notifying
 - Cancel messages if we encounter an exception so we do not attempt to process other shards after clearing the message state
 - Consistent participant filtering and Cleanup across ownership loss
 - CheckStatus.foundKnown could erroneously override validFor ranges with weaker validForAll, leading to a shard not being treated as fully truncated and preventing recovery progress

patch by Benedict and Alex Petrov for CASSANDRA-20908
94 files changed