Enable a robot to have multiple controlboard devices

[xela-95]

As per the issue title, we need that multiple controlboards can be assigned to a single robot (and of course we should allow the simulation of multiple robots at the same time).

[xela-95]

The idea is to use as key of a Control board the following:

controlBoardDeviceKey = robotScopedName / yarpDeviceName

This assumes that both the robotScopedName and yarpDeviceName are unique keys.
AFAIK the robotScopedName given by https://gazebosim.org/api/sim/8/namespacegz_1_1sim.html#a095997dc60149cb3a6cce4e8ca7d9acf it is, while for yarpDeviceName that is a responsibility of who chooses it in the controlboard yarp configuration file.

CC @traversaro