Automated emails content

[seb-koemei]

Update automated emails content, as defined here: https://docs.google.com/a/koemei.com/document/d/1gabRZ8bWThITyRFwdWSosAtqwRSil0Vnf8eEhr4lvdA/edit?disco=AAAAAEpBLE4

See also #64

[Temiola]

Need to re-edit the content to be more focused on current video learning service