Ask to install application for well-known document types

Currently the Developer tools are installed when the user double-clicks them for the first time.

Similarly, we should ask to install an application when the user double-clicks a file for which the application is not installed yet.

E.g., when you double-click a `.docx` file, then ask to install LibreOffice.

In fact, we will get this feature almost for free once we have a way for simplified `.app` bundles to tell the system which document types they can handle.