Move to cryptography and drop pyOpenSSL dependency

[jiasli]

Per https://pypi.org/project/pyOpenSSL/

Note: The Python Cryptographic Authority strongly suggests the use of pyca/cryptography where possible. If you are using pyOpenSSL for anything other than making a TLS connection you should move to cryptography and drop your pyOpenSSL dependency.

pyOpenSSL is still widely used in Azure CLI's command modules, such as role and keyvault:

azure-cli/src/azure-cli/azure/cli/command_modules/role/custom.py

Line 1376 in 38eaebb

from OpenSSL import crypto

azure-cli/src/azure-cli/azure/cli/command_modules/keyvault/_validators.py

Line 714 in a7a8869

from OpenSSL import crypto

[yonzhan]

Thank you for opening this issue, we will look into it.