bug#51565: PATCH: Update Yggdrasil to new protocol (important breaking changes)

[Ricardo Wurmus]

Ludo’s review overlapped my review.  I’ve already made all the 
changes that Ludo requested.

+ changed the descriptions
+ recorded all changes in the commit
+ added a deprecated-package in the rename commit
+ fixed indentation

Commit d9956e938343c7637647ad10b977fdb0f3b8b138 updates yggdrasil 
to 0.4.1.

--
Ricardo