Add properties: core-thin + gaunt

[ScriptRaccoon]

This PR adds the two properties "core-thin" and "gaunt" to the database.

A category is core-thin when every automorphism is trivial.
A category is gaunt when every isomorphism is the identity. Equivalently, it is skeletal and core-thin.

As a motivating example, the simplex category is gaunt. With this we can also conceptualize the proof that the simplex category has coquotients of cocongruences (cf. #115): Every core-thin category has this property.

The properties have been decided for all categories in the database. This was an easy task. Also, some previous results on one-way categories have been clarified.

PS: The category of well-ordered sets is a famous example of a core-thin category. But it is not in the database yet.