v4 error handling

We'd like to simplify the error checking and handling in h3-py v4 by:

• doing fewer correctness tests in Python/Cython code (as long as that won't allow for segfaults), deferring those correctness tests to the user (with the idea that they'd know better when those checks are and are not necessary)
• pass through the H3 core error values and messages, rather than using custom Python error types and messages

For the initial v4.0 release, we might do something simple like have only a single H3 error type (as opposed to a class hierarchy of errors) that can take on various messages, and might programmatically expose the H3 core error enum.

PRs or Issues providing examples to consider

• #241