Auto aliasing for generated SQL

While generating the final SQL for the request to some cube, we are using SQL alias property to produce different types of SQL aliases (keys, joins, etc.), if specified, and underscored cube's name otherwise. In some cases, it could be a reason for such bugs: https://github.com/cube-js/cube.js/issues/3324.

Promoted solution: apply auto alias like "C1", "C2", ... "Cn" on each cube if its SQL alias was not specified, use specified property otherwise.