"Reopen folder using..." should use a more dedicated ux solution, not notifications

Refs: https://github.com/microsoft/vscode/issues/119463 Currently we have mulitple experience to reopen the folder because there is a `Dev Container` file or a `.code-workspace` file. Both of them use notifications in order to make the user aware of this. Instead of this I propose the following: * Do not use notificaitons for this (especially painful since they appear on startup) * We should consider showing this in the empty editor area instead of action hints. Button "Reopen in Container" * Consider having this in the welcome view * We should have something in the explorer. Either a Ttitle area button, or a blue button in the empty area fyi @misolori @bpasero for ideas