ASV: Add benchmarks for groupby with multiple categories
- [ ] closes #xxxx (Replace xxxx with the GitHub issue number)
- [ ] [Tests added and passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#writing-tests) if fixing a bug or adding a new feature
- [ ] All [code checks passed](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#pre-commit).
- [ ] Added [type annotations](https://pandas.pydata.org/pandas-docs/dev/development/contributing_codebase.html#type-hints) to new arguments/methods/functions.
- [ ] Added an entry in the latest `doc/source/whatsnew/vX.X.X.rst` file if fixing a bug or adding a new feature.

Timings:

```
[ 78.57%] ··· groupby.MultipleCategories.time_groupby_extra_cat_nosort                 29.5±2ms
[ 82.14%] ··· groupby.MultipleCategories.time_groupby_extra_cat_sort                 54.4±0.1ms
[ 85.71%] ··· groupby.MultipleCategories.time_groupby_nosort                         23.0±0.2ms
[ 89.29%] ··· groupby.MultipleCategories.time_groupby_ordered_nosort                 23.3±0.1ms
[ 92.86%] ··· groupby.MultipleCategories.time_groupby_ordered_sort                   50.9±0.4ms
[ 96.43%] ··· groupby.MultipleCategories.time_groupby_sort                           50.4±0.3ms
[100.00%] ··· groupby.MultipleCategories.time_groupby_transform                       629±0.8μs
```
Thanks @rhshadrach 