Promote IO support queries to cudf API

[robertmaynard]

Description

Promote the ability to query the status of cufile and nvcomp support to the public API. It seems like these kind of questions would want to be asked by external users.

Checklist

• [x] I am familiar with the Contributing Guidelines.
• [x] New or existing tests cover these changes.
• [x] The documentation is up to date with these changes.