Refactor the inefficient function to parse PKCS#8 encrypted private keys

[akkahshh24]

Description

Currently, the function to parse the encrypted private key invokes the openssl command, writes temporary files, and reads back the decrypted output. While this works, it's very inefficient.

espresso/lib/certmanager/certmanager.go:122

// Helper function to parse PKCS#8 encrypted private keys
func parseEncryptedPKCS8PrivateKey(data, password []byte) (interface{}, error)

Go's x509 and pem standard libraries already provide support for decrypting encrypted PEM blocks using x509.DecryptPEMBlock.

Benefits

1. No call to external dependencies like openssl
2. No writing to and reading from temp files.

I'd be happy to work on this and create a pull request.

[HVBLEGENDZZ9]

Hi @akkahshh24 , can I work on this issue?

I have previously used the standard x509 and pem libraries in Go. This will be my first open source contribution if I make it happen and if there is no one working on this issue, I can pick it up and come back with an optimization for the function.

Thank you!