Change "feature" role to "source"?

[duckontheweb]

I'm assuming that the choice of "feature" as a "ml-aoi:role" value in Links was to align with the commonly used ML terminology, but in the context of geospatial/EO data I think that could lead to confusion. This role seems to correspond to the "source" rel type from the Label Extension.

Should we maybe use "label" and "source" as our roles instead to align with that language?

Should we perhaps go one step further and define a rel type instead of a new ml-aoi:role property to further align with the Label Extension?