Remove the iCubHeidelberg01 model

[traversaro]

The iCubHeidelberg01 model present in this repo is not maintained and it has not been migrated to the new model generation infrastructure at https://github.com/robotology/icub-model-generator . Unless @hu-yue is aware of anyone working on iCubHeidelberg01, I think we can drop it from the repo.

[traversaro]

cc @diegoferigo

[hu-yue]

The only person I can think of is @mhubii, if he is not using it, maybe he knows if someone is using it in Heidelberg.
cc @KevinAStein?

[mhubii]

I am using it thats true, and it would be cool to have it around until I have finished :)
But that is what branches are for, so feel free
Should I update it?

[mhubii]

and actually I am not so dependent on whether or not the model can be found here. So if it makes you feel like you could clean up your code by that, do it.

[traversaro]

This repo has been deprecated some time ago (see robotology/robotology-superbuild#542), so it is not really important to delete this specific model.