ENH: Implement categorical accessor for arrow arrays
Implements the first few methods for the categorical accessor, we could backport, but not sure if I get all of them until the release happens
This pull request is stale because it has been open for thirty days with no activity. Please [update](https://pandas.pydata.org/pandas-docs/stable/development/contributing.html#updating-your-pull-request) and respond to this comment if you're still interested in working on this. I think we would want this, but it appears this has gone stale so going to close to clear the queue