Add a way to do ExtractVIDPIDFromX509Cert via the Darwin framework

[bzbarsky-apple]

This is needed to figure out the VID/PID of the device, as claimed in its DAC, after device attestation completes.

[bzbarsky-apple]

Perhaps this API shape:

typedef NSData * MTRDeviceAttestationCertificate;

@interface MTRProductIdentity : NSObject / * Name TBD */
@property (nonatomic, readonly) NSNumber * vendorID;
@property (nonatomic, readonly) NSNumber * productID;

- (instancetype)productIdentityFromDeviceAttestationCertificate:(MTRDeviceAttestationCertificate)deviceAttestationCertificate error:(NSError * __autoreleasing *)error;

- (instancetype)init NS_UNAVAILABLE;
+ (instancetype)new NS_UNAVAILABLE;
@end

or so. Or should the "From" there be "With"?

[woody-apple]

I’d vote with. :)