gazebo-yarp-plugins 5 release plan

[traversaro]

gazebo-yarp-plugins 5 in particular:

• will drop the support for implicit wrappers
• will remove the plugins that are not useful anymore as they were made superfluos by the robotinterface

Users that need the old features can use gazebo-yarp-plugins 4.
gazebo-yarp-plugins 5 will be release on March 2022.

Blocking issues:

• Port the examples models in tutorial/model to avoid use implicit wrappers #568
• Migrate models to use new gazebo_yarp_robotinteface plugin icub-models-generator#215

Nice to have:

• A gazebo model which uses yarprobotinterface plugin crashes when the model is removed #582