Fix Modin conformance to data interchange API spec

[vnlitvinov]

System information

• OS Platform and Distribution (e.g., Linux Ubuntu 16.04): any
• Modin version (modin.__version__): cfafbb2
• Python version: any
• Code we can use to reproduce:

Describe the problem

Since data-apis/dataframe-api#74 and data-apis/dataframe-api#69 were merged, the interchange spec has changed a little bit. We need to align our implementation with it.

Source code / logs

Note on testing: some bits in https://github.com/data-apis/dataframe-interchange-tests could be looked into.

[honno]

Note on testing: some bits in https://github.com/data-apis/dataframe-interchange-tests could be looked into.

FYI updates to the test suite are in data-apis/dataframe-interchange-tests#11. Ignoring the roundtrip tests (as obviously everything's out of sync now), everything from #4763 looks good (save known issues).

pytest --disable-warnings tests/ -k "modin and not from_dataframe"