Add iDynTree::removeAdditionalFramesFromModel function to create a new model by removing additional frames from a given model

[traversaro]

Fix #1218 .

This PR adds a iDynTree::removeAdditionalFramesFromModel function that can create a new model from a given one, by removing all the additional frames, or only keeping a subset.

Example use in C++:

iDynTree::Model fullModel;

// Create model without any additional frame
iDynTree::Model fullModelWithoutAdditionalFrames;
bool ok = iDynTree::removeAdditionalFramesFromModel(fullModel, fullModelWithoutAdditionalFrames):

// Create model with only the additional frame named "example_additional_frame_name"
iDynTree::Model fullModelWithOnlyOneAdditionalFrame;
std::vector<std::string> allowedAdditionalFramesNames;
allowedAdditionalFramesNames.push_back("example_additional_frame_name");
ok = iDynTree::removeAdditionalFramesFromModel(fullModel, fullModelWithOnlyOneAdditionalFrame, allowedAdditionalFramesNames):

[traversaro]

Please ignore the gh-pages CI failure, it will be fixed by #1220 .

[Giulero]

Everything looks good to me!
Thanks a lot @traversaro!