Request: share invidivual notebooks / workspaces

I guess it's part of your plan (& related to #344) - sharing only an individual notebook/page (incl. children) - so that I can share a collection of notebooks/pages without having all my notebooks in sidebar. #### One way to do it: - creating new workspaces #### A low hanging fruit variation of this could be: - sharing direct link to a page, showing only the page and it's sub-pages