Create a GUI mockup

[toni-neurosc]

We need to have a basic outline of the GUI to show and discuss at the lab meeting of the 25th.

It does not necessarily need to be functional (e.g reading and displaying data, having interactivity with the underlying application state, etc) but it needs to be enough to give an idea of how the finished product may look.

I have started work on a very early prototype using Plotly Dash.