CTE Support

Is your feature request related to a problem? Please describe.
CTE is a feature that is integrated into other ORMs such as sqlalchemy. It allows to represent hierarchies, which are common for things like categories.

https://tortoise-orm.readthedocs.io/en/latest/examples/basic.html?highlight=recursive#recursive-relations is not exactly what I'm looking for, as it doesn't seem to be usable with QuerySet.

Describe the solution you'd like
Some simple way of using CTEs. It could be by directly specifying an option within the Meta of the model.

Describe alternatives you've considered
Direct query, which goes against the idea of using an ORM

Additional context

EDIT

Sqlalchemy CTE:
https://docs.sqlalchemy.org/en/14/core/selectable.html#sqlalchemy.sql.expression.cte

and some examples:

https://gist.github.com/cairabbit/d64fccf7cf2abe180e69c843706f46c7
https://stackoverflow.com/questions/34847869/sqlalchemy-using-a-cte-from-a-subquery-w-from-clause-specified-as-literal-te

The issue identifies QuerySet as the desired integration point and links SQLAlchemy's CTE API and examples, but names no repository files or tests. Start by reviewing QuerySet usage and the linked CTE references; done criteria would need a defined CTE API and coverage for hierarchical queries.