Mastercard-client-encryption

[Adding support for the OpenAPI Generator 7+
The OpenAPI Generator has dropped support for the 'python' library and replaced it with 'python-nextgen'. Release notes can be found [here](https://github.com/OpenAPITools/openapi-generator/releases/tag/v7.0.0)
We must update our interceptor to account for this change.

**NOTE This will break backwards compatibility**](https://github.com/Mastercard/client-encryption-python/pull/45)

- Handle use case where response body is empty for JWE

- Handle use case where response body is empty

Maintenance release
- removes the dependency from PyOpenSSL
- movies certificate management to cryptography library
- adds extra tests

There has been a recent vulnerability found in Cryptography 41.0.0 which requires an upgrade to at least 42.0.0. The current release will update our library to use the required version of the library and will remove deprecated methods and libraries