cubicweb-container #2551645 optimize container_etype relation (if it is unneeded, let's not have it) [rejected]

This is currently used to help fetch the right container_rtype.

If an entity type only lives in one container, just follow the white rabbit. Where there are several, ponder use of an attribute specifying the good container_rtype to follow.

done in1.0.0
load left0.000
closed by<not specified>