Add the support of CREATE ROLE

Similar to #14 but about CREATE ROLE

```sql
CREATE ROLE IF NOT EXISTS team_1;
```

```bash
clickhouse-sql-parser -f create-role.sql
```
output:
```bash
panic: parse statements error: line 0:7 expected keyword: DATABASE|TABLE|VIEW|DICTIONARY|FUNCTION|ROW|QUOTA|SETTINGS, but got "ROLE"
CREATE ROLE IF NOT EXISTS team_1;
       ^^^^
```