Define preferred grasping strategies for known objects

[alex-mitrevski]

In order to deal with object grasping in a more informed manner, the ontology should define preferred grasping strategies for known objects (e.g. a fork is generally grasped from the top, while a bottle from the side).

Note: The knowledge should be encoded on a class level, not just for class assertions. This should be doable with a property restriction, as for instance discussed here.

Note 2: Some groundwork for this was laid with #11