OpenSSL: Support rsa_padding_mode:pss for openssl_sign()

### Description

Use case for JWT with OAuth client credentials. I don't think this is possible with the current version of the extension, but I may be wrong.

Example command line options
```
openssl req -new -x509 -newkey rsa:4096 -sha256 -sigopt rsa_padding_mode:pss -sigopt rsa_pss_saltlen:64 -keyout key.pem -out pub.pem -nodes -days 365
```