Support query functions in `OsoClass` decorator

[bartosjiri]

The Oso's data filtering feature has options to include query functions either globally through oso.setDataFilteringQueryDefaults or specifically for individual types through oso.registerClass.

Would it be possible to add support for the latter option in the library's OsoClass decorator, please?
Unfortunately I am not knowledgeable enough to provider PR in this case.

[simenandre]

Thanks for posting this!

I'd love that feature. If someone is interested, PRs are much appreciated!