Bone map for retargeting. This class contains a hashmap that uses a list of bone names in [SkeletonProfile] as key names. By assigning the actual [Skeleton3D] bone name as the key value, it maps the [Skeleton3D] to the [SkeletonProfile]. Returns a profile bone name having [param skeleton_bone_name]. If not found, an empty [StringName] will be returned. In the retargeting process, the returned bone name is the bone name of the target skeleton. Returns a skeleton bone name is mapped to [param profile_bone_name]. In the retargeting process, the returned bone name is the bone name of the source skeleton. Maps a skeleton bone name to [param profile_bone_name]. In the retargeting process, the setting bone name is the bone name of the source skeleton. A [SkeletonProfile] of the mapping target. Key names in the [BoneMap] are synchronized with it. This signal is emitted when change the key value in the [BoneMap]. This is used to validate mapping and to update [BoneMap] editor. This signal is emitted when change the value in profile or change the reference of profile. This is used to update key names in the [BoneMap] and to redraw the [BoneMap] editor.