Add links to repositories to sidebar of module page

[hobofan]

Of the available "social" metadata, we currently only display the link to the "homepage" and the maintainers in the sidebar. We also have the links to (github) repository pages, which we could display as well.

Right now, to get to the Github repo page (which are the best place for usage instructions), one would have to go to the release notes page and from the to the main repo page.