Add Workshop filtering and groups

[jorgemoralespou]

Once we start creating content, and possibly making the tool accessible to others, it might make sense to categorize workshops and possibly modules, and provide filtering.

Example: https://kiosk-dot-codelabs-site.appspot.com/devoxx?cat=Compute

[marekjelen]

There you are pretty much trying to recreate Katacode, is it where we want to go?

//cc @thoraxe @siamaksade @gshipley @GrahamDumpleton @thesteve0

[thesteve0]

I like the left navigation between the different steps that Jorge showed. In general I like katacoda and then the google site even more and I think it would work for your environment

[siamaksade]

+1 for the left navigation