Modularizes and creates UTs for certificate validation functions

[Nicogp]

Related issue
#477

Description

This PR adds changes to modularize the certificate validation functions, it also creates a wrapper for external function calls.
It also adds UTs for new certificate validation methods.

Tests

• Compilation without warnings in every supported platform
  • Linux
  • Windows
  • MAC OS X

[TomasTurina]

Missing a deleter here?

[Nicogp]

I think not, cfHostname is the one that is released and policy is the one that is returned.

SecPolicyRef CreateSSLPolicy(bool server, const std::string& hostname) const override
        {
            // Convert std::string to CFStringRef
            CFStringRef cfHostname =
                hostname.empty()
                    ? nullptr
                    : CFStringCreateWithCString(kCFAllocatorDefault, hostname.c_str(), kCFStringEncodingUTF8);

            // Call SecPolicyCreateSSL with the CFStringRef hostname
            SecPolicyRef policy = SecPolicyCreateSSL(server, cfHostname);

            // Release the CFStringRef if it was created
            if (cfHostname)
            {
                CFRelease(cfHostname);
            }

            return policy;
        }