Support create table like maxcompute

[tobegit3hub]

We may extend the SQL syntax to support CREATE TABLE LIKE MaxCompute.

[aceforeverd]

@tobegit3hub how about CREATE TABLE .. LIKE <string_literal> or CREATE TABLE .. LIKE EXTERNAL <string_literal>, where all information from external source lives in the <string_literal>, like hdfs://.., hive://.., maxcompute://...

It avoid further changes in SQL parser