Document iCub 3 joint limits

[pattacini]

See robotology/icub-models-generator#202 (comment).

cc @traversaro

[traversaro]

The documentation in https://icub-tech-iit.github.io/documentation/icub3/icub3-joints/ (generated from /~https://github.com/icub-tech-iit/documentation/blob/a828191b77c30df153c9dcb2156b1d8cce9ec9a0/docs/icub3/icub3-joints.md) has some information on hardware limits, while software limits are missing from several joints. Documenting hardware and software limits is important as this information is encoded in several different points of the software infrastructure, including:

• Hardware Limits: contained in /~https://github.com/robotology/icub-models-generator/blob/master/simmechanics/data/icub3/ICUB_3_joint_all_parameters.csv that is feeded in the URDF and SDF files
• Software Limits: contained in Gazebo yarp controlboard configuration files's LIMITS section /~https://github.com/robotology/icub-models-generator/blob/v1.21.1/simmechanics/data/icub3/conf/gazebo_icub_left_arm_no_hand_for_no_hand_model.ini#L70
• Software Limits: contained in robot-configuration files /~https://github.com/robotology/robots-configuration/blob/v1.21.0/iCubGenova09/hardware/motorControl/left_arm-eb1-j0_1-mc.xml#L14

I could have missed some other points in which limits information is hardcoded, but even just those one highlight the importance of clearly documenting this limits. In general, as a starting point we can simply just take the values that are present in these configuration files and add them to the documentation. If those values are wrong, we can always change them later.

There are already some values that are clearly inconsistent. For example, for the shoulder roll we had a discussion in robotology/icub-models-generator#202 (comment) that the software upper limit is 163, but the documentation at the moment reports that the hardware upper limit is 150, see /~https://github.com/icub-tech-iit/documentation/blame/1ddb4dee540033d3ff10a48c5ab388d618e5021e/docs/icub3/icub3-joints.md#L125 so probably also limits already present in the document may need to be reviewed.

[traversaro]

Example of issue in which this would be useful: robotology/icub-models#104 (comment) .

[pattacini]

Same as #175 (comment).

cc @traversaro