Allow possibility to specify carrier in ports

[francesco-romano]

[diegoferigo]

@traversaro @gabrielenava Do you think this feature would still have any use case in our workflow? Otherwise I will close this issue and put it in the backlog.

[gabrielenava]

I never went through this kind of things, I just used the port block without knowing which kind of carrier was the default one, so I would say that as Simulink user I don't have any specific requirement.

[traversaro]

The need to set the carrier came out in https://github.com/robotology/yarp-device-realsense2/issues/7, in particular to address the more generic problem of https://github.com/robotology/yarp/issues/1693 .