Support for listing authenticators and deleting specific authenticator

[czf]

Changes

Adding support for listing authenticators and deleting specific authenticator

Added new methods to authentication client to support the API endpoints Added request/response classes

References

Please include relevant links supporting this change such as a: resolves #696 resolves #697

Testing

Please describe how this can be tested by reviewers. Be specific about anything not tested and reasons why. If this library has unit and/or integration testing, tests should be added for new functionality and existing tests should complete without errors.

• [x] This change adds integration test coverage

• [x] This change has been tested on the latest version of the platform/language or why not

Checklist

• [x] I have read the Auth0 general contribution guidelines

• [x] I have read the Auth0 Code of Conduct

• [x] All existing and new tests complete without errors