Make Update Manager nicer to users using changelogs

Make Update Manager better for end users by making it much easier to end-users.

The update manager currently looks very technical and this is fine for the majority of users currently using Ubuntu, however for new users I think this could be much better.

I propose for an advanced view to be kept in-place, which looks like how the system currently looks like, however a new system which would be default. This new clearer view would show a limited Changelog, displaying items which would be obvious to the user (for example, the menu layout updated or new features which are major. Not bugfixed). Then at the bottom have something like "System update will also install 21 minor items".