[dashboard] Relayout navigation in dashboard

[svenefftinge]

To simplify the UX and clarify what team context I'm acting as a user, we decided to move the org selector left and go back to a workspaces list per organization.

The current state of the design:

This change also requires moving from a global workspaces list to one per team. It would be confusing to do that change separately.

[atduarte]

@svenefftinge will the "Feedback" button be removed?

[gtsiolis]

@atduarte It's still there—sorry, the draft design skipped that. 😇

Also, Members, Usage, and Settings may move under the org selector in future iterations.

Screenshot from the preview environment in #16164

[atduarte]

Thank you! Love it 🧡

[mbrevoort]

That's a lot of options along the top, how should the design respond to narrower screens? Ideally, the gitpod dashboard shoul be "usable" all the way down to the size of a mobile device sized screen.

Here's a snapshot of the current state: