Create some troubleshooting guides

[rgbkrk]

Just like in https://github.com/nteract/nteract/issues/1327 (the originating issue for this), we should probably have some troubleshooting guides. In my heart of hearts, I was always hoping we could solve the harder user experience problems instead of documenting them. It is finally time for me to admit that we can't solve it all up front and it may be easier to reference docs to help diagnose issues.