Fix amibiguity between sensor and MAS client device names

[Nicogene]

It fixes #156

But maybe they had the same name for a reason @GiulioRomualdi @lrapetti @traversaro ?

[traversaro]

I think there are four main use cases of WBD:

• UC1: WBD used internally in the same yarprobotinterface of the physical robot
• UC2: WBD used internally of the simulated robot via gazebo_yarp_robotinterface plugin
• UC3: WBD used externally via a separately launched yarprobotinterface that connects with the physical robot
• UC4: WBD used externally via a separately launched yarprobotinterface that connects with the simulated robot

I originally wrote the file urdf/ergoCub/conf/estimators/wbd_ecub_sim.xml with device names choosen to easily support both UC2 and UC4, even if then we did not added any support for UC4 (that is tracked in #35). My final objective would be to be able to have a single wbd conf file to support all use cases, but that is another story. These PR introduces more different between UC2 and UC4, as it changes the names of client devices in UC4 to be different from the devices that provide the same sensors inside the gazebo_yarp_robotinterface plugin. Anyhow, this is not really relevant until we try to actually support UC4.

[Nicogene]

As discussed f2f w/ @traversaro, we agreed that it is fine at the end to have the mas client and the sensor w/ the same name, because it was handy if you need to use the same configuration for launching wbd internally.

Closing.