chore: update reading support for RNTuple v1

[ariostas]

This PR adds support for the first stable version of the RNTuple binary format (v1.0.0.0). It's mostly just rearranging some things and adjusting some constants. Tests will fail until scikit-hep/scikit-hep-testdata#164 is merged and released. This is still a work in progress, but it seems to mostly work already.

Note that this will completely break support for any files produced before v1

[ariostas]

This is now ready for review. All the previous functionality works again, and I fixed a small bug. All the tests should pass after scikit-hep/scikit-hep-testdata#164 is merged and released.

The remaining things that are not supported are:

• Real32Trunc and Real32Quant columns
• Suppressed columns
• Objects serialized with the ROOT streamer (which will probably never work)

Instead of waiting until I finish implementing the first two, I think it would be good to get this out so that people can try it out and we can get some feedback.

[jpivarski]

This seems to be a major overhaul to adapt for RNTuple 1.0.0.0, and it looks good!

Previously, you disabled the RNTuple-based tests. Ah! Okay, I see where the pytest.skip calls were removed. (I was looking for them as decorators, but they were module-level.)

So with the tests reinstated and new files in scikit-hep-testdata, everything works—I think it's ready to be merged! Thanks!

[jpivarski]

@all-contributors please add @ariostas for code

[allcontributors]

@jpivarski

I've put up a pull request to add @ariostas! 🎉