Initial implementation of the account index for ElasticSearch. TODO: Define schema mappings when Gerrit starts up TODO: Add support for online reindex Change-Id: I21034daa71c36a1e462e3107b0c9a7ba6392f379 Signed-off-by: Dariusz Luksza <dluksza@collab.net> Signed-off-by: David Pursehouse <dpursehouse@collab.net>