New online learning material on upgrading DAML models

Thnx to @drsk’s awesome work we now have a full fledged online course on upgrading DAML models. The course covers the full process all the way to notifying the users in the UI about the upgrade.

Make sure to check it out!

good job @drsk.

Looking forward to go trough this scenario.

Nice work @drsk! Very happy to see this in an interactive form