Hide/Remove old workshops

[kenmoini]

There are a number of workshops in the listing that are old, if at all maintained. An example would be the Source to Image workshop - I attempted it a year ago and could not get it working. Didn't matter too much since OpenShift 101 has S2I labs.

Can also hide workshops that aren't needed to be shown, such as the Example Workshop.

To do so we could simple add a draft: true to the desired _index.md files in the workshop content folders. Making it a draft simply hides it from the generated HTML.

Getting rid of the technical debt would help efforts in aligning workshops into a more standardized formatting.

Thoughts?