Qualifier field in GoAssociation Model should be removed in favor of just using negated + relation

[dougli1sqrd]

We should change how we support the Qualifier field. Currently it is a list. But actually qualifiers are always NOT, a single Relation, NOT and a Relation, or Empty (for GAF 2.1 and before). In the case that there is a Relation, we turn that into the Relation field in the GoAssociation model. Negations, whether they occur in the qualifier column or in a different one, end up going into their own boolean negated field in the GoAssociation model. And lastly if empty, for GAF (2.1 and before) at least, we compute a best guess relation to use. This should be changed to essentially not need a qualifier, as that's truly represented in the relation field.