Augment the iSkinPatches IF with getSkinPatchIndex() method #1
Description
As per https://github.com/icub-tech-iit/tickets/issues/2728#issuecomment-1561932335, we need to augment the iSkinPatches interface with a method
std::size_t getSkinPatchIndex(const std::string& name)
providing the index to the patch given its name name.