Feature
* feat: add spark functions (41)
* feat(sparkkit): add count_nulls
* feat(sparkkit): add join
* feat(sparkkit): add add_prefix
* refactor(count_nulls): add asterisk in signature
* feat(sparkkit): add add_suffix
* refactor: curry functions
* feat(sparkkit): add daterange
* refactor(daycount): rename start to d0
* refactor(daterange): rename parameters
* feat(sparkkit): add with_index
* style(with_index): positional parameter
* refactor: use spark transform func
* feat(sparkkit): add with_weekday
* feat(sparkkit): add with_endofweek_date
* style(with_index): rephrase docstring header
* feat(sparkkit): add with_startofweek_date
* refactor: use transform pattern
* build(Makefile): add commands for running slow tests
* feat(sparkkit): add validation functions
* feat(sparkkit): add evaluation functions ([`d421ac4`](https://github.com/estripling/onekit/commit/d421ac40170bf0c2d9222d1cc7cab618a73d7678))
* feat: add pandaskit (39)
* feat(pandaskit): add union
* feat(pandaskit): add join
* test: refactor pandas test_union
* feat(pandaskit): add profile ([`60e9a09`](https://github.com/estripling/onekit/commit/60e9a094cc38e05566609ed31d6d87934bf27663))
Refactor
* refactor: rename num variables + type hints (40)
* refactor: int values as n
* test: add type hints ([`6269e3a`](https://github.com/estripling/onekit/commit/6269e3a38ab07b9cb685cec769b65e3bdb8036fa))