Visual annotations meta data

[TomDijkema]

PR adds additional metadata to a Visual Annotation. The metadata, and appearance, is the same as the annotations displayed in the Side Panel. Also adds global definitions in the .env file for doi.org and handle.net as these strings are repeated a lot in the overall code. Now, the variable takes care of it. Also, if in any case the id's will not be DOIs and hosted somewhere else, the url can be changed rapidly.

Adds:

• Additional metadata to Visual Annotation
• Global definitions for doi.org and handle.net variables

[sonarcloud[bot]]

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0 Bugs
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13.2% Coverage
0.0% Duplication