Improve New Workspace flow

[uxder]

When creating a new workspace, you add a new name and then press "Create Workspace".

• You get a toast message
• You then get redirected to google authenticator (possibly because I am logged multiple google accounts)
• You are redirected to the new branch but it says "Missing site files".

I think we should:

1. Change the toast to a dialog that prevents other actions. During step1, if you start interacting with other elements on the editor page (such as clicking on a page), it throws a git error.
2. We should indicate to the user that it takes a few minutes to generate the branch. Instead of redirecting the user to the branch (that isn't ready yet), give them a link and tell them to visit it in a few minutes.

OR

alternatively, change the "missing site files" page to something more friendly like, "We are in the process of creating this branch. Please wait a few minutes".

[weeeitsmylinh]

I don't know if it's possible to create some sort of progress bar, because it took up to 10mins the last time I did this so there's no indication on whether it is working, or something broke.