Use valid linked data items for trompa-specific motivations #24
Description
We currently have 3 trompa-specific motivations used in the annotator: trompa:cueMedia, trompa:cueImage, and trompa:playlist. These motivations aren't defined anywhere. We should create custom motivations in the CE which represent these motivations so that linked data agents can determine what they are (i.e. what their skos:broader is)