Add `categorical`, `string` and `table` support to `crosstab`

Currently, `crosstab.m` requires `categorical` and `string` vector support for input arguments and `table` support as an output argument to be MATLAB compatible, as observed in the [docs](https://www.mathworks.com/help/stats/crosstab.html). This issue proposes adding support and necessary tests to `crosstab.m` as part of the ongoing `datatypes` integration effort.