New feature: option to show/export web annotation(s).

[lucaju]

Add an option to show and export the raw web-annotation in JSON-LD. This could be done on the whole document and for each individual annotation.

Expected Behaviour

1. Open an annotation.

2. Click on 'show web-annotation'.

3. A show JSON-LD in pop-up or in a section of the annotation dialog.

4. Click on export web-annotation.

5. Download JSON-LD file

Current Behaviour

Allows people to have direct access to the web-annotation structure and provide data portability.

[lucaju]

Move to Gitlab