Consider approaches to improve the diagram generation

[csarven]

Many questions and possible paths here.

When there are many notifications it will take a long time for the client to fetch each (an HTTP request per notification) and to build the SVG diagram. Initial considerations:

• Should there be a single file containing all notifications? This is still an issue once for the client.
• Stream fetch and display. Potentially slowing down the rendering if the SVG is updated continuously - Perhaps drop the d3-force simulation. Advantage being that the user can see something right away. Perhaps fetch in batches?
• Instead of fetching all notifications on load, the UI should make the calls based on user input eg display only the citations, and filtering.
  ..