[Proposal] Introduce support to retrieve `crypto:PrivateKey` or `crypto:PublicKey` by directly using the content

[ayeshLK]

Summary

Cryptographic private keys and certificates are represented as crypto:PrivateKey or crypto:PublicKey in Ballerina.
Hence, it should be possible to retrieve a crypto:PrivateKey or a crypto:PublicKey by just using the content of the
private key or the certificate.

Goals

• Introduce support to retrieve crypto:PrivateKey or crypto:PublicKey by directly using the content

Motivation

In Ballerina, cryptographic private keys and certificates are represented as crypto:PrivateKey and crypto:PublicKey,
respectively. Currently, a developer must provide the file path to retrieve either a crypto:PrivateKey or a
crypto:PublicKey. However, for greater flexibility, developers should also have the option to retrieve these
keys using the raw content of the file.

Description

As mentioned in the Goals section the purpose of this proposal is to introduce support to retrieve
crypto:PrivateKey or crypto:PublicKey by directly using the content.

The key functionalities expected from this change are as follows,

• API to retrieve crypto:PrivateKey using the content of the private key.
• API to retrieve crypto:PublicKey using the content of the certificate

API additions

A new API will be added to retrieve crypto:PrivateKey using the content of the private key.

public isolated function decodeRsaPrivateKeyFromContent(byte[] content, string? keyPassword = ()) returns crypto:PrivateKey|crypto:Error;

A new API will be added to retrieve crypto:PublicKey using the content of the certificate.

public isolated function decodeRsaPublicKeyFromContent(byte[] content) returns crypto:PublicKey|crypto:Error;

[MohamedSabthar]

Implemented