Idea to Production (Mark's video)

closes https://gitlab.com/gitlab-com/blog-posts/issues/238

This is a draft, needs a lot of work! I'm not happy with it yet, can be much better...

Please @markpundsack and @afolson would you mind taking a first look to polish this out?

If the 2nd part (the use-cases) is complicating things - or looks out of context, we can simply remove it.

Thank you!