Add table related DDLs support in SQL Parser

1. showTablesStatement:
SHOW TABLES

2. descTableStatement:
DESCRIBE [ EXTENDED] [[catalogName.] dataBasesName].tableName

3. alterTableStatement:
ALTER TABLE [[catalogName.] dataBasesName].tableName
RENAME TO newTableName

4. ALTER TABLE [[catalogName.] dataBasesName].tableName
SET ( name=value [, name=value]*)