ddl: support alter table add/drop/alter check constraint

[AilinKid]

Signed-off-by: AilinKid 314806019@qq.com

What problem does this PR solve?

support alter table with constraint ddl action.

create table t(a int);

**Add constraint**:
alter table t add constraint haha check(a >1);

> Attention: check constraint will fetch the data from table to check.

**Alter constraint**:
alter table t alter constraint haha enforced;

> Attention: not enforced check constraint will allow the violated data to insert, but when change a constraint from not enforced to enforced, it will fetch the data to check constraint.

**Drop constraint**:
alter table t drop constraint haha;

What is changed and how it works?

Schema State: None -> Write Only -> Public
None: Node in this state will not perceive the constraint existence, and the inserted data may violate the check constraint.

Write Only: Node in this state will actually see check constraint existence, but the inserted data will check the constraint rule. If broken, ddl fails.

Public: on the way from Write Only to Public, ddl owner will fetch the old data previous to Write Only state, and check the data whether it's satisfied the check constraint rule. If broken, ddl fails.

Check List

Tests

• Unit test
• Integration test

Code changes

• Has interface methods change

Release note

• Write release note for bug-fix or new feature.
• ddl: support alter table add/drop/alter check constraint

[imtbkcat]

@AilinKid please fix conflict

[AilinKid]

Migrated to the new pr #12 in which I add more cancel test about alter constraint.