Add release notes

For now, it will be kept simple. Release notes will be in an html file that has a pre section with the actual release notes that are handcrafted. If there is some further collaboration with others in the future, this may not be the most appropriate going forward. Will worry about that later 😄

Add a link to this release notes (target=_new) in the opening page where the type is chosen.

Maybe at the bottom, instead, in a small div that is just ALWAYS at the bottom that contains version number and the link? That seems most reasonable. Tucked away, out of the way.