Add initial draft of migration guide
Add initial draft of migration guide

NOTE: this is more of a checklist and outline than a guide
at the moment.

dylans/dgrid,dylans/dgrid,kfranqueiro/dgrid,maier49/dgrid,dylans/dgrid,maier49/dgrid,kfranqueiro/dgrid,kfranqueiro/dgrid,maier49/dgrid