feat: cardinality metric for categorical data (#128)

* cardinality + tests draft

* add and refactor tests, add lazy fixture dep

* add pytest-lazy-fixtures to dev dependencies

* fix type check

* attempt to fix type issue in pipeline

* still trying to fix type issue

* more typing issues

* more types

* types;

* types

* adjust type

* more types

* add column names to cardinality method

* add column type alias

* simplify and remove types

* fix type issue in pipeline

* remove type alias

* type issue