[Feature] Support sort key, add ORDER BY grammar to assign sort key.

[Linkerist]

Feature request

Is your feature request related to a problem? Please describe.

now sort key is primary key, can not assign non-key columns.
it's ok:

CREATE TABLE test (
  `k1` int,
  `k2` int,
  `k3` int,
  `v1` int,
  `v2` int,
  `v3` int,
  `v4` int,
  `v5` int
) ENGINE=OLAP
PRIMARY KEY(`k1`, `k2`, `k3`)
COMMENT "OLAP"
DISTRIBUTED BY HASH(`k1`, `k2`, `k3`) BUCKETS 1
PROPERTIES ("replication_num" = "1");

it's not ok:

CREATE TABLE test (
  `k1` int,
  `k2` int,
  `k3` int,
  `v1` int,
  `v2` int,
  `v3` int,
  `v4` int,
  `v5` int
) ENGINE=OLAP
PRIMARY KEY(`k1`, `k2`, `k3`)
ORDER BY(`v2`, `v4`)
COMMENT "OLAP"
DISTRIBUTED BY HASH(`k1`, `k2`, `k3`) BUCKETS 1
PROPERTIES ("replication_num" = "1");

need to support the latter.

Describe the solution you'd like

add ORDER BY grammar, and use the assigned columns to sort, and do some adaptive things for these.