Support WITH clause

[morenoh149]

Throws on

const parser = require('js-sql-parser');
const ast = parser.parse('WITH t as ( delete from foo ) Delete from bar;')
console.log(JSON.stringify(ast, null, 2));

[albin3]

It will be supported after #2 , clause follows https://dev.mysql.com/doc/refman/8.0/en/with.html