core: frontend: version-chooser: show/link to release notes / docs

### Current behaviour

Version Chooser notifies when new versions are available, but doesn't specify what new features or bug fixes are included, so the main reason for updating is the idea of "staying up to date", which isn't very exciting.

### Expected or desired behaviour

It would be cool if updates could show the release notes/changelog between the current version and the new one being considered, or at least the new features in that particular release. Ideally this would be provided as a few major points with a link to the full release notes, but if that's not feasible it would still be nice to have the release notes either embedded or linked to.

It would also be nice if installed versions could include a link to the docs for that version. This would be extra accessible if the docs came embedded for local hosting in each version (or were made accessible via an extension with the same version numbering as BlueOS), but a hyperlink to the relevant online docs for the active version would still be an improvement.

### Prerequisites

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