Get visualization to display proper -& Put visualizations in the right place

[KleinRana]

Currently:

1. A vega-lite spec is loaded in pages/datasets/[...slug].vue
2. it can then be used to populate a VegaView element in components/dataset/TabDashboard.vue

However, you would like to

1. Load all specs belonging to a specific dataset at once (from all files in one folder, or even all from one file??)
2. and then embed the Vegaview elements in the .md-file for that specific dashboard

[Veldhoen]

Specs are now loaded from a directory.
They are not embedded in the .md-file (at least not yet), but are generated directly in Dashboard component - in alphabetical order