Added Handling Auth Errors

[allerter]

This PR adds handling exceptions raised by RateLimitMiddleware.authenticate. All exceptions are caught and sent to RateLimitMiddleware .on_auth_error so that the appropriate response can be returned.

A few notes:

• I added except Exception as exc to catch all exceptions and not just EmptyInformation. This is because the authentication function might raise other exceptions. For example, the auths.jwt.create_jwt_auth can raise the following exceptions: EmptyInformation, ValueError, AssertionError, KeyError and jwt.exceptions.DecodeError.
• I didn't know where it would be appropriate to add more tests, so I just added one to test_redis to keep coverage happy. But I don't think that's the right place for that test.
• I ran coverage and it returned 99% (probably as expected), but I didn't find any guide for styling or mypy checks if there any.

Closed #12

[abersheeran]

I didn't know where it would be appropriate to add more tests, so I just added one to test_redis to keep coverage happy. But I don't think that's the right place for that test.

You can add a file test_core.py in tests.

[abersheeran]

Thank you for your contribution! After fixing another issue, I will release a new version.