Add CREATE MATERIALIZED VIEW statement

CREATE MATERIALIZED VIEW [IF NOT EXISTS] [db_name.]materialized_view_name
  [COMMENT materialized_view_comment]
  [
   [ROW FORMAT row_format] 
   [STORED AS file_format]
     | STORED BY 'storage.handler.class.name' [WITH SERDEPROPERTIES (...)]
  ]
  [LOCATION hdfs_path]
  [TBLPROPERTIES (property_name=property_value, ...)]
  AS select_statement;