Epic: New Workspace Input

[jldec]

Summary
The goal of this feature is to provide users with a great experience for starting workspaces.

Context
The existing "new workspace" UI has several limitations.

• It does not support opening workspaces on arbitrary repo context URLs
• It requires navigating to a workspaces list to click on the "New Workspace" button
• The modal UI feels too small and not commensurate with the importance of the New Workspace action.

Description
This epic aims to fix those limitations with the following:

• A text input which supports copy-paste of git repo context URLs
• An auto-suggest completion feature offering a list of pre-fetched repos for quick selection, when users start typing the name or other text suggestive of the repo they want
• A keyboard binding to bring up the New Workspace feature from anywhere in the dashboard
• A cleaner user interface which maintains functional parity with the old New Workspace modal.
  Design improvements for the new "New Workspace" modal #8088

Future goals (not in scope for this epic) include

• Smarter auto-suggest based on user behavior or other inputs
• Promotion of the New Workspace page to serve as the default landing page for the dashboard
• Support for use by unauthenticated users prior to sign-up or login

Value
Starting workspaces is a key feature of Gitpod, and one that deserves to be as smooth and simple as possible, for both new and returning users.

[jldec]

See #3715 (comment) for additional UX ideas. (from @shaal)

GitKraken has a nice interface to open an existing repo from Github, Gitlab, etc.
Whatever git hosting the user gave Gitpod access to, can list repos, branches and PR, directly from Gitpod UI.

GitKraken screenshot for opening an existing repo

also from #3715 (comment)

It will have a dropdown for adding prefixes, like #prebuild (and if there are more) before the repo URL
It will allow adding environment variables, with + button for every new environment variable.