Add support for virtual can

[ardrabczyk]

I'm going to use it like that in an algorithm for auto-detecting CAN speed (I also need listen-only mode for that #174):

canInfo, err := d.Info()
if err != nil {
        return err
}

if canInfo.Type == candevice.VcanLinkType {
        log.Println("Type is vcan, cancel auto-detecting CAN speed")
        return nil
}

SetBitrate() and others don't have to changed, they will return netlink receive: operation not supported errors. Receive() and TransmitFrame() will continue working without any changes.

There are no tests, I thought I could add them to pkg/candevice/device_integration_test.go but nothing there uses vcan0 at this moment.

[Edholm]

Thanks for the contribution 💯

[Edholm]

Please change your commit message to follow conventional commit style

[ardrabczyk]

Sorry, should have run make before pushing. One test still fails though.