Add support for Origin CA certificates

[GerardSmit]

This PR adds support for Origin CA certificates.

API documentation

• Get: https://developers.cloudflare.com/api/operations/origin-ca-list-certificates
  Note: the documentation is missing that the query zone_id is required. Without this parameter, you'll get an error 1012 (Please provide a zone id when requesting a stored certificate, or fetch by serial number).
• GetDetails: https://developers.cloudflare.com/api/operations/origin-ca-get-certificate
• Add: https://developers.cloudflare.com/api/operations/origin-ca-create-certificate
• Revoke: https://developers.cloudflare.com/api/operations/origin-ca-revoke-certificate

Usage example:

using RSA key = RSA.Create(2048);

string domain = "example.com";

CertificateRequest request = new CertificateRequest(
    $"CN={domain}",
    key,
    HashAlgorithmName.SHA256,
    RSASignaturePadding.Pkcs1);

CloudFlareResult<Certificate> result = await client.Certificates.AddAsync(new NewCertificate
{
    CertificateSigningRequest = request.CreateSigningRequestPem(),
    Hostnames = [$"*.{domain}", domain],
    RequestType = CertificateType.OriginRsa
});

X509Certificate2 originCertificate = new X509Certificate2(Encoding.UTF8.GetBytes(result.Result.OriginCertificate));
X509Certificate2 certificate = originCertificate.CopyWithPrivateKey(key);

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud