Add Stacks page under Che's Dashboard

[slemeur]

Add Stacks list under Che's Administration page

We will add a new tab under the Che's Administration page on the User Dashboard: "Stacks"
In this page we will display the list of all the Stacks that are registered on Che. (ie stacks.json)

[TylerJewell]

Maybe this should be a primary left nav item called Stacks? If we are going to do a lot more with stacks sharing and notification among shares users then that would not be an administration issue - it would just be stacks.

[slemeur]

OK +1

Updated design:

[TylerJewell]

+1 on the location - definitely want this as a primary object. @slemeur - lets also think about some of the onboarding workflows for new users into the Che product once stack editing is available.

If you are a new user in Che, today we push you to create your first workspace. We want to get them with a private repository that they can make a commit with. Should we be thinking a bit more about pushing people into creating their first custom stack?

1: Browsing existing stacks for their contents. I noticed that many of the stacks have descriptions and component lists that could be updated (version numbers and more complete items).

2: Browsing the different stacks by operating system. I noticed that we do not have a filter component on the ready-to-go stacks, but we do on the stack library. We should be consistent.

3: How will changes to stacks have notifications to users? This is a super tricky issue as we can track changes to the meta information, but we will not necessarily be able to track changes to internal images.

4: When users create new stacks, creating from an existing one or a new from a template will be a big deal. We will want to make it really fun for people to create new stacks over time.

Ok to start breaking these issues into different issues - just starting the discussion.

[slemeur]

Cross link with #2316