Add a progress bar

[VAISHALI-DHANOA]

Add a progress bar to indicate where in the onboarding are you

[VanessaFediuk]

Possible way: Use a D3 tree and color visited nodes ( and edges) differently and make the current node bigger

I need to look at how we can do this dynamically but using a tree and styling to show the progress seems to be the only possibility to implement a progress bar with branching

http://www.d3noob.org/2014/01/tree-diagrams-in-d3js_11.html