Display gene product 2 term relations

[hattrill]

The gp2term relations are not displayed on AmiGO - just the old qualifiers. Can we update this to match the current annotations, please?

[kltm]

Noting actively blocked upstream by: owlcollab/owltools#312
That's "technically" the main issue here (amigo isn't smart enough itself to have opinions this complicated about displays), but it's good to have this as a shadowing ticket so that we don't loose track.

To reiterate some parts of that, the original owltools loader was created in a very GAF 2.0 kind of world and does not properly pass through gp2term relations not included from then (there is a lot of hard-coded bits around relation handling).