Remove design-docs folderThis has turned into a graveyard for ideas. It only servesto confuse people at this point. We have found it more productiveto either- use GitHub Epics and issues for smaller design questions- use Google Docs for larger topics (e.g. native publishing)These documents quickly go out of date once a feature is implemented.They are not a replacement for good user and code documentation.Many of the documents are about features that we never ended upimplementing. Having those documents still around might lock usinto a certain way of thinking about a problem. Instead we shouldhave a fresh look at it when we actually want to start working on it.