Improved Dashboards (upgrade Dash)

[PGijsbers]

To decide: what will we do exactly?

Make dashboards (e.g. dataset analysis) more user friendly and quicker.

There are several problems with the current Dash visualizations:

• Font, font-size, and used colors all severely limit the accessibility of the Analysis tabs.
• The Dashboards are at times very slow (for example, retrieving run results for a task) -> perhaps we can avoid loading (as much) data through graphql or subsampling.

We also should migrate to the latest Dash (1.3->2.6). It might also be worthwhile to do a quick survey to see if there are no better options available at this time.

[PGijsbers]

@joaquinvanschoren Please provide @SubhadityaMukherjee with access to the student's work in this matter, so we can see what we reuse.