* List still dirty files if backup fails

Fixes #113627

* Move dirty file list into showErrorDialog

Fix #113747

For #109277

- Add more explicit two phase structure to api
- Make opener pass along label when registered

This workbench service handles opening external uris. Unlike the core OpenerService, it also has logic for configuring a default opener and prompting if multiple openers are availble for a given uri

fixes #111843

Part of https://github.com/microsoft/vscode-remote-release/issues/4046

Part of microsoft/vscode-remote-release#4046

//cc @aeschli