add support for CREATE DATABASE

```
CREATE {DATABASE | SCHEMA} [IF NOT EXISTS] db_name
    [create_specification] ...

create_specification:
    [DEFAULT] CHARACTER SET [=] charset_name
  | [DEFAULT] COLLATE [=] collation_name
  | DEFAULT ENCRYPTION [=] {'Y' | 'N'}
```
https://dev.mysql.com/doc/refman/8.0/en/create-database.html