Render linking annotations as hyperlinks

[tomcrane]

https://iiif-canvas-panel.netlify.app/docs/examples/rendering-links

As with #70, the implementation is dependent on #94 - the list below might change. For example:

<!-- prevent default follow behaviour -->
<canvas-panel id="cp" follow-annotations="false" />

<!-- allow cp default behaviour in anno rendering, but at least provide some styles -->
<canvas-panel id="cp"
    highlight-css-class="anno-hilite"
    link-css-class="anno-link"    
/>

^^ That might not be how we do this, see #94

• Create and render a DisplayAnnotation that wraps Default rendering of annotations with linking motivation and renders a hyperlink
• DisplayAnnotations supports options with body-processing callback (also implies Body class)
• Provide API that allows handling of existing annotations, so the developer can control when and how they are displayed on the canvas surface.