PLT-6472: Basic Elastic Search implementation. (#6382)

* PLT-6472: Basic Elastic Search implementation.

This currently supports indexing of posts at create/update/delete time.
It does not support batch indexing or reindexing, and does not support
any entities other than posts yet. The purpose is to more-or-less
replicate the existing full-text search feature but with some of the
immediate benefits of using elastic search.

* Alter settings for AWS compatability.

* Remove unneeded i18n strings.

store/sql_post_store.go

@@ -1287,3 +1287,30 @@ func (s SqlPostStore) GetPostsCreatedAt(channelId string, time int64) StoreChann
 
 	return storeChannel
 }
+
+func (s SqlPostStore) GetPostsByIds(postIds []string) StoreChannel {
+	storeChannel := make(StoreChannel, 1)
+
+	go func() {
+		result := StoreResult{}
+
+		inClause := `'` + strings.Join(postIds, `', '`) + `'`
+
+		query := `SELECT * FROM Posts WHERE Id in (` + inClause + `) and DeleteAt = 0 ORDER BY CreateAt DESC`
+
+		var posts []*model.Post
+		_, err := s.GetReplica().Select(&posts, query, map[string]interface{}{})
+
+		if err != nil {
+			l4g.Error(err)
+			result.Err = model.NewAppError("SqlPostStore.GetPostsCreatedAt", "store.sql_post.get_posts_by_ids.app_error", nil, "", http.StatusInternalServerError)
+		} else {
+			result.Data = posts
+		}
+
+		storeChannel <- result
+		close(storeChannel)
+	}()
+
+	return storeChannel
+}