Improve wizard to restart workspace

[TylerJewell]

When you stop a workspace we show a dialog with some problems. User is in the context of a workspace, he does not need to select which worksapce to restart. The workspace to be restarted is the one selected in the left nav bar. We have a second dialog to ask the user if he wants to restart from snapshot. We can improve this wizard.

[TylerJewell]

@slemeur - not ok with using the popup design. But whatever we do for the workspace loading, we would reapply here.

[slemeur]

Updated design. We'll use a toast at the top of the IDE

[vitaliy-guliy]

Spent 3 days