frontend: Snapshot library: view EXIF data

### Current behaviour

We automatically store some EXIF data when capturing snapshots, but users need to open them in some other program to be able to view/query that.

### Expected or desired behaviour

It would be nice if we could just expose it directly as part of a preview in the snapshots library.

### Prerequisites

- [x] I have checked to make sure that a similar request has not already been filed or fixed.

Start by locating the snapshots library and its preview entry point, then trace where EXIF data is already stored during snapshot capture. Expose that existing metadata in the preview and verify that users can view or query it directly in the library.

Written by the indexing model from the issue text.