This pr implements the list default partition referred in related #15507.
It's similar as GreenPlum's default's partition which would store all data not satisfying prior partition key's
constraints and optimizer wouldn't filter default partition which means default partition would be scanned
each time you try to select data from one table with default partition.
User could either create one table with default partition or alter add one default partition.
```sql
PARTITION LIST(key) {
PARTITION p1 values in (xx,xx),
PARTITION DEFAULT
}
ALTER TABLE XXX ADD PARTITION DEFAULT
```
We don't support automatically migrate data inside default partition which meets newly added partition key's
constraint to newly add partition when alter add new partition. User should select default partition using new
constraints as predicate and insert them to new partition.
```sql
insert into tbl select * from tbl partition default where partition_key=xx;
```
c39914c0a0