*: support invisible database / table

[zimulala]

What problem does this PR solve?

Support the invisible database/table. e.g.

CREATE TABLE tbl_name (create_definition,...) INVISIBLE
ALTER TABLE tbl_name VISIBLE;

This visible database/table is the normal database/table. This invisible database/table is invisible which means this database/table only can be changed the database/table schema. We only can do alter database/table and drop database/table operation on invisible database/table. In order to know the structure of the invisible database/table, the show create database/table operation is supported on the invisible table.

Relate to pingcap/parser#674
It's used for pingcap/br/issues/87.

What is changed and how it works?

create database/table ... invisible creates a database/table with the state of delete-only.
alter database/table ... visible changes a database/table to public.

Check List

Tests
Unit tests need to be added.

[zimulala]

Unit tests need to be added.

[zimulala]

This feature is not currently required