Optimizations of av-store (#2223)

* Store all chunks and in a single transaction

* Adds chunks LRU to store

* Add pruning records metrics

* Use honest cache instead of LRU

* Remove unnecessary optional cache

* Fix review nits that are fixable

polkadot/node/network/availability-distribution/src/lib.rs

@@ -1036,7 +1036,6 @@ where
 		AvailabilityStoreMessage::StoreChunk {
 			candidate_hash,
 			relay_parent,
-			validator_index,
 			chunk: erasure_chunk,
 			tx,
 		}