Write project aims/summary

[davanstrien]

topics to cover

• [ ] tl;dr
• [ ] IIIF as a source of data
• [ ] IIIf as an annotation interface
• [ ] ml with historic images
• [ ] generating training data in a GLAM setting

[davanstrien]

@davanstrien draft with shifting focus in mind. Leave some gaps for the annotation questions that remain