Tests: move RecoverAfterNodesTests to org.elasticsearch.gateway.local and increase BLOCK_WAIT_TIMEOUT to 10s

The tests were still in org.elasticsearch.gateway.none but the none gateway was removed.
[STORE] Expose ShardId via LeafReader rather than Direcotry API

Today we try to fetch a shard Id for a given IndexReader / LeafReader
by walking it's tree until the lucene internal SegmentReader and then
casting the directory into a StoreDirecotory. This class is fully internal
to Elasticsearch and should not be exposed outside of the Store.

This commit makes StoreDirectory a private inner class and adds dedicated
ElasticsearchDirectoryReader / ElasticserachLeafReader exposing a ShardId
getter to obtain information about the shard the index / segment belogs to.

These classes can be used to expose other segment specific information in
the future more easily.